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美军标MIL-D-3464E-干燥剂、包装要求

美军标MIL-D-3464E-干燥剂、包装要求
美军标MIL-D-3464E-干燥剂、包装要求

MIL-D-3464E

21 April 1987 SUPERSEDING

MIL-D-3464D

17 May 1966

(See 6-7)

MILITARY SPECIFICATION

DESICCANTS, ACTIVATED, BAGGED, PACKAGING

USE AND STATIC DEHUMIDIFICATION

This specification is approved for use by all Departments and Agencies of

the Department of Defense.

1. SCOPE

1.1 Scope. This specification covers bagged, chemically inert, dehydrating agents that prevent corrosion and mildew by adsorbing the moisture from the air of an enclosed space.

1.2 Classification. The bagged desiccant shall be furnished in the following types, as specified (see 6.2):

Type I General purpose.

Type II Non-dusting.

Type III For specific conditions (8 and 16 units only).

2. APPLICABLE DOCUMENTS

2.1 Government documents.

2.1.1 Specifications and standards. The following specifications and standards form a part of this specification to the extent specified herein. Unless otherwise specified, the issues of these documents shall be those listed in the issue of the Department of Defense Index of Specifications and Standards (DODISS) and the supplement thereto, cited in the solicitation.

SPECIFICATIONS

FEDERAL

QQ-A-250/4 - Aluminum Alloy 2024, Plate and Sheet.

QQ-B-637 - Brass, Naval: Rod, Wire, Shapes, Forgings, and

Flat Products with Finished Edges (Bar, Flat Wire, and Strip).

ú???????????????????????????????????????????????????????????????????????????????3Beneficial comments (recommendations, additions, deletions) and any pertinent 33data which may be of use in improving this document should be addressed to: 33Commander, Naval Sea Systems Command, SEA 55Z3, Department of the Navy, 33Washington, DC 20362-5101 by using the self-addressed Standardization Document33Improvement Proposal (DD Form 1426) appearing at the end of this document 33or by letter. 3à??????????????????????????????????????????????????????????????????????????????ù

FEDERAL (Continued)

QQ-M-44 - Magnesium Alloy Plate and Sheet (AZ31B).

RR-S-366 - Sieve Test.

TT-E-485 - Enamel, Semigloss, Rust-Inhibiting.

PPP-C-96 - Cans, Metal, 28 Gage and Lighter.

PPP-D-723 - Drums, Fiber.

PPP-P-704 - Pails, Metal: (Shipping, Steel 1 through 12

Gallons).

MILITARY

MIL-P-116 - Preservation, Methods of.

MIL-I-8835 - Indicator, Humidity, Card, Chemically Impregnated.

STANDARDS

MILITARY

MIL-STD-105 - Sampling Procedures and Tables for Inspection by Attributes.

MIL-STD-129 - Marking for Shipment and Storage.

MIL-STD-147 - Palletized Unit Loads.

MS26507 - Indicator Card, Desiccant Relative Humidity

(8% +/- 5%)

MS27684 - Drum, Metal-Shipping and Storage 3 to 12 Gallons.

2.1.2 Other Government publication. The following other Government

publication forms a part of this specification to the extent specified herein. Unless otherwise specified, the issues shall be those in effect on the date of the solicitation.

DEPARTMENT OF TRANSPORTATION (DOT)

Specification 37A - Steel Drums. Single-Trip Container. Removable Head Required.

(Application for copies should be addressed to the Superintendent of Documents, Government Printing Office, Washington, DC 20402.)

(Copies of specifications, standards, and publications required by

contractors in connection with specific acquisition functions should be obtained from the contracting activity or as directed by the contracting activity.)

2.2 Other publications. The following documents form a part of this specification to the extent specified herein. Unless otherwise specified, the issues of the documents which are DoD adopted shall be those listed in the issue of the DODISS specified in the solicitation. Unless otherwise specified, the issues of documents not listed in the DODISS shall be the issue of the nongovernment documents which is current on the date of the solicitation.

AMERICAN SOCIETY FOR TESTING AND MATERIALS (ASTM)

A 569 - Standard Specification for Steel, Sheet and Strip, Carbon

(0.15 Maximum Percent), Hot-Rolled, Commercial Quality.

(DoD adopted)

UNIFORM CLASSIFICATION COMMITTEE AGENT

Uniform Freight Classification Ratings, Rules and Regulations

(Application for copies should be addressed to the Uniform Classification Committee Agent, Tariff Publication Officer, Room 1106, 222 South Riverside

Plaza, Chicago, IL 60606.)

NATIONAL MOTOR FREIGHT TRAFFIC ASSOCIATION, INC., AGENT

National Motor Freight Classification

(Application for copies should be addressed to the National Motor Freight

Traffic Association, Inc., ATA TRAFFIC Dept., 2200 Mill Road, Alexandria, VA 22314.)

(Nongovernment standards and other publications are normally available

from the organizations which prepare or which distribute the documents. These documents also may be available in or through libraries or other informational services.)

2.3 Order of precedence. In the event of a conflict between the text of

this specification and the references cited herein (except for associated

detail specifications, specification sheets or MS standards), the text of this specification shall take precedence. Nothing in this specification, however,

shall supersede applicable laws and regulations unless a specific exemption has been obtained.

3. REQUIREMENTS

3.1 Qualification. Bagged desiccant furnished under this specification

shall be products which are authorized by the qualifying activity for listing

on the applicable qualified products list at the time set for opening of bids

(see 4.2 and 6.3).

3.2 Material.

3.2.1 Desiccant. The desiccant shall be newly manufactured and shall be nondeliquescent.

3.3 Definition of desiccant unit. Desiccant will be purchased on the

basis of adsorption capacity. A desiccant unit is that quantity of desiccant,

as received, which will adsorb at equilibrium with air at 25 degrees Celsius

at least the following quantities of water vapor:

(a) 3.00 grams at 20 percent relative humidity (R.H.), and

(b) 6.00 grams at 40 percent R.H.

3.4 Unit weight. The weight of desiccant constituting a desiccant unit

is defined as the unit weight. Unit weight shall not exceed 50.0 grams. Unit weight shall be specified by the manufacturer when submitting qualification samples (see 4.2.1), and shall be verified by the qualifying laboratory using

the methods specified in 4.6.1. The unit weight thus approved shall be used

in all subsequent inspections.

3

3.4.1 Unit adsorption capacity (equilibrium conditions). The actual weight

of water vapor adsorbed by a unit weight of desiccant in equilibrium with air

at 25 degrees C, when tested as specified in 4.6.1, is defined as the unit adsorption capacity.

3.4.1.1 In qualification tests, unit adsorption capacity shall be at least:

(a) 3.00 grams at 20 percent R.H., and

(b) 6.00 grams at 40 percent R.H.

3.4.1.2 When testing a bagged desiccant, an allowance shall be made for

normal manufacturing variations. In connection with such inspection testing, unit adsorption capacity shall be at least:

(a) 2.85 grams at 20 percent R.H., and

(b) 5.70 grams at 40 percent R.H.

3.5 Unit volume. The volume of desiccant constituting a desiccant unit

is defined as the unit volume. Unit volume shall be not greater than 45.0 milliliters (mL) when tested as specified in 4.6.2.

3.6 Unit content per bag. The number of desiccant units contained in

each bag (unit content) shall be clearly marked on the bag label. When tested as specified in 4.6.10, bags of desiccant shall actually contain at least 95 percent of the number of units indicated on the bag label.

3.7 Unit adsorption rate. When tested as specified in

4.6.4, the bagged desiccant, as received, shall adsorb in 7 hours the weight of water vapor in accordance with table I.

TABLE I. Unit adsorption rate requirements.

ú???????????????????????????????????????????????????????????

3 3 At 40 percent 3 At 80 percent 3

3 Bag size, 3 R.H. (gram) 3 R.H. (gram) 3

3 units 3 minimum 3 minimum 3

???????????????????????????????????????????????????????????′

3 16 and smaller sizes 3 0.25 3 0.70 3

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3.8 Humidity control. A unit of desiccant shall prevent a closed metal

box from exceeding 60 percent R.H., when tested as specified in 4.6.3.

3.9 Adsorption capacity and rate after reactivation. After the reactivations and tests specified in

4.6.5, bagged desiccant shall retain at least 90 percent of the original unit adsorption capacity, and at least 80 percent of the

original unit adsorption rate. Reactivation conditions shall be recommended by the manufacturer (see 4.2.1 and 3.17). However, the reactivation temperature shall be not less than 245OF (118.30C), and the time for each reactivation

shall not exceed 24 hours.

4

3.10 Dusting.

3.10.1 Type I (all sizes) and type III (B and 16 units). When tested as specified in

4.6-6, the weights of dust found shall be in accordance with

table II.

TABLE II. Dusting requirements.

ú????????????????????????????????????????????????????????????????????????????3 3 3At least six3At least eight3 No more than 3No more than33 3 3of the dust 3 of the dust 3two dust values3 one dust 33 3 Number 3values shall3 values shall 3 shall be in 3value shall 33Bag size,3of bags 3 not exceed 3 not exceed 3 the range 3 exceed 33 units 3 tested 3 (mg) 3 (mg) 3 (mg) 3 (mg) 3????????????????????????????????????????????????????????????????????????????′316 3 12 3 5.0 3 --- 3 60.0 to 200.0 3 200 33 8 3 12 3 2.5 3 --- 3 60.0 to 200.0 3 200 33 4 and 3 12 3 --- 3 0.5 3 60.0 to 200.0 3 200 33 smaller3 3 3 3 3 3à?????????á????????á????????????á??????????????á???????????????á????????????ù3.10.2 Type II. When tested as specified in 4.6.6, type II desiccant shall produce not more than 1/2 milligram of dust, regardless of bag size.

3.11 Corrosiveness. The bagged desiccant and the desiccant by itself in contact with steel, brass, magnesium, and aluminum shall show no increase in corrosion when tested as specified in

4.6.7.

3.12 Bag durability.

3.12.1 Types I, II and III. Bags in which the desiccant is packaged shall

not puncture, tear or burst, and the tie strings shall not break when tested

as specified in 4.6.8.

3.12.2 Type III only. Bags in which the desiccant is packaged shall not puncture, tear or burst nor show visible evidence of leaching of the desiccant through the bag material when tested as specified in

4.6.8.4. The test water used for immersion shall contain not more than 5 milligrams of non-combustible material per 8 units of desiccant when tested as specified in 4.6.8.4.1.

3.13 Resistance of bagging material to reactivation temperature. When reactivated and tested as specified in

4.6.9, the desiccant bag shall not puncture, burst, or otherwise fail.

3.14 Bag size. Type I and 11 desiccants shall be furnished in bags in the fractional unit sizes of 1/6, 1/3, and 1/2; the unit size 1, and the multiple unit sizes of 2, 4, 8 and 16 as specified (see 6.2).

3.1

4.1 Type III desiccant shall be furnished in bags in the multiple unit sizes of 8 and 16 as specified (see 6.2).

3.15 Tie strings, Unless otherwise specified in the contract or order, bags of 16-unit size or larger shall be provided with tie strings having a minimum length of 7 inches.

3.16 Particle size. The particle size distribution shall be as shown in

table III.

TABLE III. Particle size.

ú???????????????????????????????????????????

3 Sieve number 3 Distribution, percent 3

???????????????????????????????????????????′

3 1/2 inch [1] 3 Retained (max) 0.0 3

3 80 3 Retained (min) 96.0 3

à?????????????????á????????????????????????ù

[1] The permissible variation in average openings shall be 3 percent. The permissible variations in maximum openings shall be 5 percent. The wire

diameter shall be 0.094 to 0.122 inch.

3.17 Bag markings. Each desiccant bag shall be marked durably and legibly

with the following information:

Nomenclature: Desiccant, Activated, Bagged, Packaging Use and Static

Dehumidification

Specification: MIL-D-3464

Type I, II, or III, as applicable

Manufacturer's designation

Unit content __________________________

Reactivation temperature in bag _______ degrees F

Reactivation time ______ hours

Manufacturer's name and address

4. QUALITY ASSURANCE PROVISIONS

4.1 Responsibility for inspection. Unless otherwise specified in the contract or purchase order, the contractor is responsible for the performance of all inspection requirements as specified herein. Except as otherwise specified in the contract or purchase order, the contractor may use his own or any other facilities suitable for the performance of the inspection requirements

specified herein, unless disapproved by the Government. The Government

reserves the right to perform any of the inspections set forth in the specification where such inspections are deemed necessary to assure supplies

and services conform to prescribed requirements.

4.1.1 Responsibility for compliance. All items must meet all requirements

of sections 3 and 5. The inspection set forth in this specification shall become a part of the contractor's overall inspection system or quality program. The absence of any inspection requirements in the specification shall not

relieve the contractor of the responsibility of assuring that all products or supplies submitted to the Government for acceptance comply with all

requirements of the contract. Sampling in quality conformance does not authorize submission of known defective material, either indicated or actual, nor does it commit the Government to acceptance of defective material.

4.2 Qualification tests. Qualification tests shall be conducted at a

laboratory satisfactory to the Naval Sea Systems Command (NAVSEA).

Qualification tests shall consist of the tests specified in 4.6.

6

4.2.1 Forwarding instructions. Qualification test samples shall be forwarded to a laboratory satisfactory to NAVSEA. These samples shall be plainly identified by securely attached durable tags marked with the following information:

Samples for qualification test

Desiccant, Activated, Bagged, Packaging Use and Static Dehumidification Unit content _________________________

Unit weight _________________________ grams

Bagging material _____________________

Methods of closure ___________________

Reactivation temperature _____________ degrees F

Minimum reactivation time ____________ hours

Manufacturer's code number ___________

Submitted by (manufacturer's name and address and date) for

qualification tests in accordance with MIL-D-3464.

Type I, II, or III, as applicable

Location of plant which produced samples

________________________________________

Tests authorized by ____________________

(reference authorizing letter)

4.2.2 Qualification sample. A qualification sample shall consist of the number of bags listed in table IV for each kind of bag material submitted for qualification.

TABLE IV. Qualification sample size.

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3 Bag size, 3 Number of 3 Bag size, 3 Number of 3

3 units 3 bags 3 units 3 bags 3

?????????????????????????????????????????????????????????????????′

3 16 3 44 3 1/2 3 53 3

3 8 3 41 3 1/3 3 61 3

3 4 3 39 3 1/6 3 86 3

3 2 3 41 3 --- 3 --- 3

3 1 3 45 3 --- 3 --- 3

à????????????????á???????????????á??????????????á????????????????ù

4.3 Sampling for quality conformance test.

4.3.1 Lot. A lot shall consist of 1 day's production or of any fractional

day's production of one bag size which constitutes completion of a manufacturing run.

4.3.2 Method of sampling. An inspection test sample shall consist of the number of bags of desiccant listed in table V for each different bag material.

7

MIL-D-3464E

TABLE V. Inspection sample size.

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3 Bag size, 3 Number of 3 Bag size, 3 Number of 3

3 units 3 bags 3 units 3 bags 3

?????????????????????????????????????????????????????????????????′

3 16 3 93 3 1/2 3 120 3

3 8 3 84 3 1/3 3 144 3

3 4 3 81 3 1/6 3 216 3

3 2 3 84 3 --- 3 --- 3

3 1 3 96 3 --- 3 --- 3

à????????????????á???????????????á??????????????á????????????????ù

4.3.2.1 The bags shall be opened only at the test laboratory. Each sample

shall be divided into three equal representative portions, which shall immediately be placed in clean, dry containers, which, when sealed, shall be

air- and moisture-tight. Extreme care shall be taken to ensure that the material is exposed for a minimum time, and that the containers are closed and sealed immediately. Each bag shall be given a cursory check to ensure immediate rejection of bags or lots if the bags are punctured or excessively dirty. Samples shall be identified with the name of the manufacturer, name of the material, the specification number, the number of units, the reactivation instructions, the contract number, and the lot number.

4.4 Inspection.

4.4.1 Examination of filled containers. A random sample of filled containers shall be selected from each lot in accordance with MIL-STD-105 at inspection level I, and acceptable quality level of 2.5 percent defective to verify compliance with this specification regarding fill, closure, marking, and other requirements not involving tests. Containers shall be examined for defects of container and closure, for evidence of leakage, and for unsatisfactory markings; each sample-filled container shall also be weighed to determine the amount of the contents. Any container in the sample having one or more defects, or being under required fill, shall not be offered for delivery. If the number of defective containers in any sample exceeds the acceptance number for the appropriate sampling plan of MIL-STD-105, this shall be cause for rejection of the lot represented by the sample.

4.4.2 Quality conformance tests. Each of the samples selected as specified

in 4.3.2 shall be subjected to the following tests:

TABLE VI. Quality conformance inspection.

ú????????????????????????????????????????????????????????????????????????? 3 Test 3Requirement3Test paragraph3 ?????????????????????????????????????????????????????????????????????????′ 3Unit adsorption capacity 3 3.4.1 3 4.6.1 3 3Unit volume 3 3.5 3 4.6.2 3 3Humidity control 3 3.8 3 4.6.3 3 3Unit adsorption rate 3 3.7 3 4.6.4 3 3Adsorption capacity after reactivation 3 3.9 3 4.6.5 3 3Dusting 3 3.10 3 4.6.6 3 3Corrosiveness 3 3.11 3 4.6.7 3 3Bag durability 3 3.12 3 4.6.8 3 3Resistance of bag to reactivation temperature3 3.13 3 4.6.9 3 3Unit content of package 3 3.6 3 4.6.10 3

4.4.2.1 In addition to the tests specified in 4.4.2, type III desiccant

shall be subjected to the test specified in 4.6.8.4.

4.5 Retests and rejections. Failure of the material to conform to any

one of the requirements of this specification during inspection shall be cause for rejection of the lot represented. If, in the opinion of the contractor,

the failure was due to faulty test method, the tests may be repeated on the contractor's retained sample. In case of a controversy, the test shall be repeated on the Government retained sample. Failure of any two of the three samples to meet the requirements shall be cause for final rejection of the lot represented.

4.6 Tests.

4.6.1 Unit adsorption capacity.

4.6.1.1 Apparatus. The general arrangement of the apparatus shall be as

shown on figure 1. The fitting comprising the inlet, outlet, and petticoat bubbler for each saturator bottle shall have a ground glass stopper to fit the bottle. The saturator bottles and bubbler shall be constructed so that with 1 liter of solution in the bottle the upper holes of the bubbler shall be not more than 3 inches nor less than 1 inch below the surface of the liquid. Each of the six saturator bottles shall be filled with 1 liter of identical sulfuric acid solutions to give the desired relative humidity at 25 degrees C in accordance with table VII.

TABLE VII. Relative humidity solutions. [1]

ú??????????????????????????????????????????????????????????????????????????????3 3 Percent by 3 R.H. percent 3 Sp.gr. [2] 3 Sp.gr. [2] 33Solution 3 weight 3 at 25 deg. C 3 20 deg./4 deg. C 3 77 deg./60 deg. F3??????????????????????????????????????????????????????????????????????????????′3Hú2?SOú4?3 58.2 3 20 3 1.4789 3 1.4754 33Hú2?SOú4?3 47.8 3 40 3 1.3739 3 1.3715 33Hú2?SOú4?3 38.4 3 60 3 1.2889 3 1.2859 33Hú2?SOú4?3 26.2 3 80 3 1.1894 3 1.1853 3à?????????á????????????á????????????????á??????????????????á??????????????????ù

[1] Relative humidity represents values that would be obtained in a closed static system. The actual effluent relative humidities will be slightly

below these nominal values.

[2] Specific gravity measurements should be made at either indicated temperature using a precision hydrometer with smallest subdivision 0.0005 unit.

4.6.1.1.1 The sample-containing bottle shall be a Nesbitt, Fleming, or

other standard form of adsorption bulb. The bulb shall be provided with a suitable closure to prevent diffusion. For routine tests, the temperature of the room in which the tests are being conducted shall be controlled to 25 +/-

20 degrees C. For referee tests, the room temperature shall be controlled to plus or minus 1 degree C. For routine tests, the temperature variation within the saturator bottles, the inlet air, and the sample-containing bottle during any one run shall not exceed plus or minus 1 degree C. A desiccant trap filled with activated desiccant under test shall be placed in front of the saturator bottles to pick up any absorptive impurities in the inlet air.

4.6.1.2 Procedure. A 6- to 10-gram sample of the desiccant shall be weighed

to the nearest milligram in the tared absorption bulb. Care shall be

exercised to ensure that the material is exposed to the air for a minimum time. The adsorption bulb shall then be connected to the apparatus and the air flow adjusted to 4 +/- 0.5 liters per minute with the by-pass closed. If the manometer indicates the pressure in the last bottle to be greater than 1 inch mercury, the bleed-off line shall then be cracked open until the manometer indicates less than 1 inch and that point maintained for the balance of the run. When using the by-pass, an occasional check shall be made of the amount

of air passing through the adsorption bulb by diverting the by-pass air from

the flowmeter to atmosphere through the "tee" connection. The flowmeter

reading will then indicate the actual air flow through the adsorption bulb. Periodically the adsorption bulb shall be removed from the train, the stopcocks closed and the bulb weighed. This process shall be repeated until two successive weighings, approximately 1 hour apart, show a weight variation not exceeding 5 milligrams. The test shall be considered complete if at any time the minimum specification values are attained. It will generally be found that the weight will rise to a maximum arid then decrease slightly before approaching a constant value. The adsorption capacity of the desiccant shall be determined by the following equation for the specified relative humidities. UG

Unit adsorption capacity = ????

W

Where:

U = unit weight (grams)

W = original weight of sample taken (grams)

G = Gain in weight of samples (grams)

4.6.1.3 Alternate apparatus. A commercial environmental chamber is suitable as an alternate apparatus for this test. The chamber shall be capable of

a relative humidity percent range of 20-80 at 25 degrees C. For routine tests, the temperature of the chamber in which the tests are being conducted shall be controlled to 25 +/- 2 degrees C. For referee tests, the chamber temperature shall be controlled to plus or minus 1 degree C.

4.6.1.4 Alternate procedure. A 6- to 10-gram sample of the desiccant shall be weighed to the nearest milligram on a glass dish. Care shall be exercised to ensure that the material is exposed to the air for a minimum time. The dish shall then be placed in the environmental chamber. Periodically the dish shall be removed from the chamber and weighed. This process shall be repeated until two successive weighings, approximately 1 hour apart, show a weight variation not exceeding 5 milligrams. The test shall be considered complete if at any time the minimum specification values are attained. It will generally be found that the weight will rise to a maximum and then decrease slightly before approaching a constant value. The adsorption capacity of the desiccant shall be determined by the following equation for the specified relative humidities. Unit adsorption capacity = UG

????

W

10

Where:

U = unit weight (grams)

W = original weight of sample taken (grams)

G = Gain in weight of samples (grams)

4.6.2 Unit volume. A clean, dry, 100 mL graduated cylinder shall be weighed

to the nearest 0.1 gram. The cylinder shall be filled to any convenient level with activated desiccant and weighed again. The cylinder shall be tapped on a resilient surface, such as heavy sheet rubber, until the volume of desiccant remains constant between two successive 1-minute tapping periods. The volume of desiccant in the graduated cylinder shall be read. The unit volume shall

be calculated by the following formula:

Unit volume = U V

?????

W

Where:

U = unit weight (grams)

W = original weight of sample taken (grams)

V = volume of sample as read in the graduate (mL)

4.6.3 Humidity control.

4.6.3.1 Apparatus. The apparatus shall consist of an open end steel box

(see figure 2) measuring 12 by 12 by 11 inches having a flanged, removable

1/4-inch brass cover on the open end and painted on the outside with aluminum paint. The brass cover shall be held to the box by 24 evenly-spaced wing bolts. The box shall have an internal open end copper shell, 10 by 10 by 10 inches, evenly spaced from all sides except the covered side. The surrounding side shall be filled with glass wool insulation. The brass cover of the box shall be provided with an access port sealed with a no. 13 rubber stopper for the introduction of the desiccant. One insulated wall shall have attached the necessary instrumentation for the accurate measurement of temperature and R.H. (plus or minus 1-1/2 percent R.H.) under static conditions. A cylinder 1-3/8 inches in diameter and 3 inches long, fabricated from 100-mesh copper screening shall be attached to the small end of the no. 13 rubber stopper.

4.6.3.2 Procedure. Suspend 125 to 150 grams of activated desiccant in a bag inside the box and close it with a no. 13 stopper without the copper screen sample holder. Place the box and desiccant in an oven at 38 +/- 1 degree C

until the relative humidity within the box remains at approximately zero for 4 hours. Leave the box in the oven, but withdraw the bag of desiccant. Fill the copper screen cylinder with one unit of the desiccant test sample. Pour 5 mL of water onto the floor of the box and then insert a no. 13 stopper with a copper screen cylinder of desiccant attached. Allow the apparatus to come to equilibrium humidity by letting stand overnight at 38 +/- 1 degree C. Place the box in a refrigerator maintained at 5 +/- 2 degrees C. Read the temperature and relative humidity in the box at 15-minute intervals for a period of 5 hours and record the maximum relative humidity attained. The temperature drop shall be not less than 1.8 degrees F (1 degree C) nor greater than 10.8 degrees F (6 degrees C) in any 10-minute interval during the first hour of cooling.

11

4.6.4 Unit adsorption rate.

4.6.4.1. Apparatus. The apparatus shall consist of a bell jar of 5- to

10-liter capacity fitted with an air inlet at the top and open to the atmosphere at the bottom or a wide mouth jar with a stoppered inlet at the top and a hole near the bottom open to the atmosphere. The test container shall be large enough to allow the free flow of air over all of the surface of the bag and not be in contact with any part of the bag. The flow of air in the test container shall be from the top air inlet to the bottom of the container. Saturator bottles for supplying air to the test container shall be similar to those specified in 4.6.1.1. The concentrations of sulfuric acid specified in table VII for 40 percent and 80 percent R.H. shall be employed.

4.6.4.2 Procedure. Accurately weigh the bag with its contents. Immediately suspend the bag in a jar by its strings or by a spring clamp. Start the air flowing through the saturation bottles at the rate of 4 +/- 1/2 liters per minute, passing the effluent air into the inlet tube of the jar. After 7 hours, remove the bag and weigh. Calculate the unit adsorption rate as follows:

G

Unit adsorption rate = ???

U

Where:

G = gain in weight of bagged desiccant (grams)

U = unit content marked on the bag

4.6.5 Adsorption capacity and rate after reactivation. Suspend two bags of desiccant in an enclosed atmosphere at 25 +/- 1 degree C over an open container of water for a minimum of 16 hours. Remove the bags and suspend them in a circulating air type oven at the reactivation conditions recommended by the manufacturer (see 3.17). Repeat the above saturation and reactivation. Place in a desiccator and cool. Determine the unit adsorption capacity of the contents of one bag of desiccant in accordance with 4.6.1, except that the determination shall be made and reported at 40 percent R.H. only. Determine the unit adsorption rate on the other bag in accordance with 4.6.4 except that the determination shall be made and reported at 80 percent R.H. only.

4.6.6 Dusting.

4.6.6.1 Apparatus. The container used for the determination for 16-unit and smaller bags shall consist of an approximately 3-gallon can with fully removable lid in accordance with MS27684. The inside of the can shall be cleaned to the metallic surface. All internal seams shall be leaded or soldered and worked smooth to an even uniform surface. The vibrating apparatus shall consist of a table that can be moved in a circular vibratory motion in a vertical plane by an eccentric with a 1/2-inch throw at 300 +/- 5 cycles per minute.

4.6.6.2 Procedure. Place the desiccant bag combination to be tested in

the cleaned test container in such a manner that the bag is flat on the bottom of the container with the printed legend up and in a readable position. Whenever the bag is too large to lie flat in the container it shall be positioned so that the bottom portion of the bag lies along the bottom seam of the container with the upper portion of the bag resting on the vertical surface

diametrically opposite. The cover of the container shall be tightened in place place and the container firmly attached to the vibratory table. The container

and contents shall be vibrated for 30 minutes. At the completion of the

vibration period, the container shall be opened carefully and any dust on the inside surface of the cover shall be brushed into the container with a camel-

hair brush. The desiccant bag combination shall be removed from the can and

any adhering dust brushed from the surface of the bag into the container. The dust collected in the container shall be brushed into a dried weighing bottle

with top affixed and carefully and quickly weighed. Twelve 16-unit or smaller bags shall be run from each lot being tested. All dust values shall be

reported.

4.6.7 Corrosiveness. Grind 20 grams of desiccant, retaining the portion that passes a U.S. No. 40 sieve and is held on a U.S. No. 80 sieve in accordance

with RR-S-366. Place this 40 to 80 mesh material in a desiccator maintained at

25 degrees C and 60 percent R.H. for a minimum of 24 hours. In a similar

fashion place four bags of desiccant in a desiccator maintained at 25 degrees C and 60 percent R.H. for a minimum of 24 hours. Prepare a 2- by 1- by 1/8-inch

and a 14- by 4- by 1/4-inch specimen each of hot rolled steel in accordance

with ASTM A 569, brass in accordance with QQ-B-637, magnesium alloy in

accordance with condition 0 of QQ-M-44, and aluminum in accordance with

condition T3 of QQ-A-250/4 by grinding and polishing one surface to 6 to 8

root mean square microinches. Clean two panels of each metal by successive treatments with:

(a) Hot toluene (210 degrees F), 2 minutes immersion.

(b) Hot acetone (120 degrees F), quick rinse.

(c) Hot methanol (120 degrees F), quick rinse.

During and after cleaning, handle the panels either with forceps and an the

edge only, or with wire loops passing through holes previously drilled near one corner. Do not blot dry, but immediately after the methanol rinse, dry each panel for 1 to 2 (but not more than 2) minutes in an oven at 100 degrees F. Cover

one-half of each small panel with a unbagged desiccant, and cover one-half of

each large panel with a bag of desiccant and place the panels in a desiccator maintained at 60 percent R.H. by sulfuric solution in accordance with table

VII. Place the desiccator in an oven maintained at 38 +/- 1 degree C for 72 hours. Remove the panels from the desiccator, carefully brush with a camel-

hair brush, and visually compare the covered and uncovered surfaces for extent

of corrosion.

4.6.8 Bag durability.

4.6.8.1 Strength of bag as received. Remove a bag of desiccant from the

shipping container and drop it 20 times from a height of 10 feet to a concrete surface so that it lands on its large flat side but not on its edge or end. Examine the bag for puncturing, bursting, or other failure. Replicate to a

total of three bags for each lot. If one of the bags tested fails, seven

additional desiccant-bag combinations shall be tested. Cause for rejection

shall be failure of two out of 10 bags at from 10 to 20 test drops or failure

of any one bag at 10 or less test drops.

4.6.8.2 Strength of bags at low temperature. Store three representative

desiccant-bag combinations in a constant temperature box at minus 40 +/- 5 degrees C for 6 hours. Then remove from temperature box and immediately drop

each bag three times in 15 seconds from a height of 10 feet to a concrete

surface so that they land on their large, flat sides, but not on their edges or ends. Examine for evidence of puncturing, bursting, or other failure. If one of the bags fails, seven additional desiccant-bag combinations shall be tested, of which none shall fail.

4.6.8.3 Vibration resistance. When tie strings are provided, fasten three representative bags by their tie strings to a backboard mounted on a vibration table having a circular vibratory motion of 300 cycles per minute and an amplitude of plus or minus 1/2 inch in the vertical plane. Make the suspension so that the bags are on the right-hand face of the backboard when viewed from the end on which the rotation of the eccentrics is clockwise. Attach the tie strings to the screw hooks on the backboard so that the strings are as close to vertical as possible, consistent with the type of tie strings and bag, and 1/2 inch from the backboard, with the top of the bag 3 +/- 1/2 inches below the hooks and the bottom of the bag not less than 1/2 inch above the table as the bag rests against the backboard when the machine is idle. Vibrate for a 2-hour period and inspect the bags for rupture of the seams. Tie strings shall not break nor cause failure of the bag by effecting breaking or tearing or the severance of over two stitches oil each end of the sewn seam which secures the tie strings to the bag.

4.6.8.4 Resistance to hot water (type III only). Three representative desiccant bag combinations shall be individually and completely immersed in distilled water and maintained at a temperature of 200 +/- 5 degrees F for a period of 2 hours. Upon completion of the immersion period, the bags shall be removed from the water and immediately subjected to the test specified in

4.6.8.1. Cause for rejection shall be as specified in 4.6.8.1.

4.6.8.4.1 The water in which the desiccant bag was immersed shall be filtered through a no. 41 Whatman filter paper or equal. The filter paper containing the residue shall then be placed in a tared platinum crucible, slowly charred, and then ignited in a furnace at a temperature of 1000 to 1050 degrees C for a period of 1 hour. The crucible shall then be removed, placed in a desiccator, allowed to cool and reweighed. The amount of noncombustible material for eight units of desiccant shall be computed as follows:

Initial wt of crucible - final wt of crucible X 8 = Wt of noncombustible/

????????????????????????????????????????????? ?????????????????????

Unit size of bag tested 8 units of desiccant

The average value obtained for three determinations shall be reported.

4.6.9 Resistance of bag to reactivation temperature. Reactivate three representative bags of desiccants, in accordance with manufacturer's instructions (see 4.2.1). Cool to room temperature in a desiccator. Remove from the desiccator and drop each separately three times from a height of 10 feet to a concrete surface so that they land on their large flat side but not on their edge or end. Examine the bags carefully for evidence of puncturing, bursting, or other failure.

4.6.10 Unit content of package. Weigh a clean, dry beaker and empty the

entire contents of a representative bag into it and reweigh. Determine unit content of bag by the following formula:

14

A - B

Unit content = ??????

C

Where:

A = Weight of beaker and desiccant in grams

B = Weight of empty beaker in grams

C = Unit weight in grams

4.6.11 Particle size.

4.6.11.1 Apparatus. The shaker to be employed in conducting particle-size

tests shall operate with a single eccentric circular motion at 285 +/- 10 revolutions per minute and with a tapping action of 150 +/- 5 strokes per

minute to obtain dependable sieve analysis. To permit flexible operation,

the shaker shall accommodate one to six 8-inch sieves with one pan and cover.

4.6.11.2 Procedure. Nest the sieves in the order of decreasing sizes with

the largest sieve on top and a pan at the bottom. Weigh a sample of approximately 150 grams of the material and place it on the top sieve of the nest. Place the nest of sieves with the cover in the testing machine and

vibrate for 3 minutes plus or minus 3 seconds with a tapper in operation. Weigh the residue on each sieve to within 0.5 gram and calculate the percentage of desiccant retained on each sieve immediately following the shaker operation. Use the sum of all individually retained weights as the total weight of the sample.

4.7 Inspection of packaging. Sample packages and packs, and the inspection of the preservation-packaging, packing and marking for shipment and storage shall be in accordance with the requirements of section 5 and the documents specified therein.

5. PACKAGING

(The packaging requirements specified herein apply only for direct Government acquisition. For the extent of applicability of the packaging requirements

of referenced documents listed in section 2, see 6.5.)

5.1 Preservation-packaging. Preservation-packaging shall be level A or C,

as specified (see 6.2).

5.1.1 Quantity per container. Bags of desiccant of one size shall be

packaged in containers of uniform capacity. The containers shall be approximately full and bagged desiccant packaged to avoid damage to the packaging material. The quantity of bags per container per bag size, shall be as follows:

15

5-gallon can 5-gallon pail

Bag size No. of bags No. of bags

1/6 1200 1200

1/3 650 700

1/2 450 550

1 250 300

2 130 150

22-gallon 200-pound capacity

24-gauge drum drums

Bag size No. of bags No. of bags

1 1000 1300

2 650 800

4 400 500

8 240 300

16 120 150

5.1.2 Each container enclosing bagged desiccant shall contain at least one humidity indicator card in accordance with MS26507 which meets all of the requirements of MIL-I-8835. No cushioning or overpacking shall be included in containers.

5.1.3 Level A.

5.1.3.1 Five-gallon can. The 5-gallon capacity cans shall be in accordance with type V, square, of PPP-C-9

6. Where cans are made of electrolytic tinplate, the tin coating shall be approximately 0.50 pound per base box of 112 sheets, 14 by 20 inches (see 6.2). Cans shall be provided with a top opening of 6-15/16 inches in diameter and fitted with a leak-proof multiple-friction plug type closure. Handles will not be required.

5.1.3.2 Five-gallon pail. The 5-gallon capacity pail shall be in accordance with type II, class 3 of PPP-P-704 (see

6.2).

5.1.3.3 Drums.

5.1.3.3.1 Metal drums. Unless otherwise specified (see

6.2), metal drums

shall be of 24-gauge construction in accordance with 178.131 of Department of Transportation Specification 37A. Drums shall be provided with leakproof,

air-tight bolt locking ring type covers. Each movable cover shall be fitted with a tubular flow-in or sponge rubber gasket. The gasket shall be securely affixed so that it will remain in place when the cover is removed. The entire exterior surfaces of the drums shall be protected with a corrosion-resistant coating in accordance with type II of TT-E-485. Drum dimensions shall be as follows:

Capacity Dimensions (approximate inside)

gallons Height Diameter

inches inches

22 21 18

30 (200 pounds) 27-11/16 18-1/4

5.1.3-3.2 Fiber drums. When specified (see

6.2). fiber drums in accordance with PPP-D-723, type III, grade A, class 2, may be used for packaging the 200-pound capacity quantities.

5.1.4 Level C. The bagged desiccant shall be packaged in leakproof, air-tight containers which shall provide protection against deterioration, moisture

pick-up and damage during shipment from the supply source to the first

receiving activity for immediate use. Fiber drums, when used, shall be in accordance with PPP-D-723, type I, grade A, class 2.

5.2 Packing. Packing shall be level A, B, or C as specified (see

6.2).

5.2.1 Level A.

5.2.1.1 Cans shall be arranged and packed level A in accordance with the appendix to PPP-C-9

6.

5.2.1.2 Pails and drums will require no further packing. When specified

(see 6.2), pails and drums shall be palletized for shipment in accordance with MIL-STD-147.

5.2.2 Level B.

5.2.2.1 Cans shall be arranged and packed level B in accordance with the appendix to PPP-C-9

6.

5.2.2.2 Pails and drums will require no further packing. When specified

(see 6.2), pails and drums shall be palletized for shipment in accordance with MIL-STD-147.

5.2.3 Level C. The bagged desiccant, packaged as specified, shall be packed

in a manner which will ensure arrival at the destination in satisfactory condition and which will be acceptable to the carrier at lowest rates. Containers and packing shall conform to the Uniform Freight Classification Rules, National Motor Freight Classification Rules or other carrier regulations as applicable to the mode of transportation.

5.3 Marking. In addition to any special marking required (see

6.2), interior packages, exterior shipping containers and pelletized unit loads shall be marked in accordance with MIL-STD-129. Each container shall be marked with the following additional information:

"Caution: This container contains desiccant. Due to the moisture

properties of desiccant, this container positively must not be opened for any longer period than is absolutely necessary for withdrawals. Withdrawals shall be limited to the quantity

intended to be used. The container shall be tightly resealed immediately after any withdrawal."

17

6. NOTES

6.1 Intended use. Bagged desiccants covered by this specification are

intended for use in removing moisture from gases, including air, and liquids,

as follows:

(a) Generally applicable for static dehumidification of packages and

closed spaces in order to prevent corrosion, mold, or mildew.

(b) Method II packaging. The use of desiccants in method II packaging is covered by MIL-P-116, which also specifies formulae for computing the proper quantity of desiccant to be used.

(c) Type III desiccant in 8 and 16 unit bags is intended for use in

areas where a danger exists of accidental flooding by water

(200 degrees F maximum). The durability of the bag material, and

seams thereof, should be sufficient to prevent contamination of a

system by accidental dispersal of desiccant material.

(d) Type II desiccant is intended for use in critical packaging

applications where dusting cannot be tolerated.

6.1.1 This specification is intended for use in the acquisition of new

bagged desiccant.

6.2 Ordering data. Acquisition documents should specify the following:

(a) Title, number, and date of this specification.

(b) Type of desiccant required (see 1.2).

(c) Number of units per bag (see 3.14 and 3.14.1).

(d) Applicable level of preservation-packaging and packing required

(see 5.1 and 5.2).

(e) Size container required (see 5.1.3.1 and 5.1.3.2).

(f) When other than 24-gauge drums are required (see 5.1.3.3.1).

(g) When bagged desiccant may be furnished in fiber drums (see

5.1.3.3.2).

(h) When palletization of pails and drums is required (see 5.2.1.2

and 5.2.2.2).

(i) Special marking required (see 5.3).

6.3 Qualification. With respect to products requiring qualification, awards will be made only for products which are, at the time set for opening of bids, qualified for inclusion in Qualified Products List QPL-3464 whether or not

such products have actually been so listed by that date. The attention of the contractors is called to these requirements, and manufacturers are urged to arrange to have the products that they propose to offer to the Federal Government tested for qualification in order that they may be eligible to be awarded contracts or purchase orders for the products covered by this specification. The activity responsible for the Qualified Products List is

the Naval Sea Systems Command, SEA 55Z3, Department of the Navy, Washington, DC 20362-5101 and information pertaining to qualification of products may be obtained from that activity. Application for qualification tests shall be made in accordance with "Provisions Governing Qualification SD-6" (see 6.3.1).

18

6.3.1 Copies of "Provisions Governing Qualification SD-6" may be obtained upon application to Commanding Officer, Naval Publications and Forms Center, 5801 Tabor Avenue, Philadelphia, PA 19120.

6.4 Particular attention should be paid to acquisition of the smallest

size exterior container commensurate with the probable rate of use of the desiccant. The material rapidly loses its dehydrating strength when exposed

to air so that use of containers requiring a minimum of openings will help ensure most efficient use of the desiccant.

6.5 Sub-contracted material and parts. The packaging requirements of referenced documents listed in section 2 do not apply when material and parts are acquired by the contractor for incorporation into the equipment and lose their separate identity when the equipment is shipped.

6.6 Subject term (key word) listing.

Adsorption

Desiccant, activated

Dusting

Reactivation

6.7 Changes from previous issue. Asterisks are not used in this revision

to identify changes with respect to the previous issue due to the extensiveness of the changes.

Custodians: Preparing activity:

Army - EA Navy - SH

Navy - SH (Project 6850-0803)

Air Force - 68

Review activities:

Army - MI, AT

Navy - SA, AS, OS

DLA - GS, DS

User activities:

Navy - CG

Army - ME, AR, SM

19

干燥剂标准介绍

干燥剂标准介绍 1、药品食品干燥剂相关标准 药品食品用干燥剂的标准主要是由国家食品药品监督管理局制定的药品包装容器(材料)标准:《药用固体纸袋装干燥剂标准》YBB00122005。 该标准规定了对“固体制剂滤纸袋包装的细孔球型硅胶干燥剂”的要求,其中除了对干燥剂袋外观、强度,吸附剂的含水率、吸湿率等干燥剂基本性能要求外,着重就干燥剂在有害物质含量(如:砷含量等),微生物限度,脱色性能等方面进行了规定。 威胜针对药用食品用干燥剂,专门制定了两种产品标准,分别为《小圆柱干燥剂产品标准》WS-QWS-824-55和《透明条连续式干燥剂产品标准》WS-QWS-824-56,这两种产品在满足YBB00122005的基础上,增加了吸湿速度要求、粉尘要求、交货方式等要求,另外有使产品更适合进行自动化分装的要求。具体差异见下表: WS-QWS-824-55 WS-QWS-824-56 备注 硅胶原料 含水率 ≤% ≤% ≤% WS 的产品要求含水 率更低,更注重干燥剂低湿下的吸湿能力;小圆柱 产品规定原料粒度是为 了更好的控制产品粉尘。 粒度 — ~4mm — 吸湿率 20%RH ,≥%; 50%RH ,≥%; 90%RH ,≥%; 20%RH ,≥%; 50%RH ,≥%; 20%RH ,≥%; 50%RH ,≥%; 包材 荧光测 试 不得含有 不得含有 — 由于透明条连续式干燥剂的包材以及小圆柱干燥剂的外壳均为塑料,其理化性能指标还参照了YBB00122002以及YBB00172004中的相关规定。 坤含量 ≤% — ≤% 铅含量 ≤% ≤% ≤% 脱色试 验 无色 无色 无色 溶剂残留量 ≤10mg/m2 ≤10mg/m2 ≤10mg/m2 干燥剂袋 外观 干净整洁无破损 干净整洁无破损 干净整洁无破损 吸湿速度要求的制定,能使干燥剂在快速恒定吸收水分、控制湿度方 面有更好的表现。 牢度(抗跌性) 1.2m 高跌 落无破损 1m 高5次跌落无破损 1m 高5次跌落 无破损 粉尘 — 无粉尘 无粉尘 吸湿速 度 — 25度40%RH 25度60%RH 下

高中化学干燥剂总结

高中化学干燥剂小结 1、酸性干燥剂:浓硫酸、P2O5、硅胶 1)浓硫酸(强氧化性酸) 2)P2O5(酸性白色粉末)、 3)硅胶(它是半透明,内表面积很大的多孔性固体,有良好的吸附性,对水有强烈的吸附作用。含有钴盐的硅胶叫变色硅胶,没有吸水时呈蓝色,被水饱和后呈粉红色。) 2、碱性干燥剂:碱石灰、CaO、固体NaOH 1)碱石灰(它是白色固体,主要成分CaO和NaOH)、 2)CaO(它是白色固体, 碱性氧化物)、 3)固体NaOH(强碱) 3、中性干燥剂:无水CaCl2、CuSO4 1)无水CaCl2(白色多孔固体)、 2)CuSO4(白色粉末,吸水程度较小,一般用来检验水的存在,吸水后变成蓝色CuSO4·5H20) 二、常见气体的分类 中学阶段常见的气体,按酸碱性也可分为三种: ①酸性气体:CO2、SO2、NO2、Cl2、HCl、H2S、HBr、HI等 ②碱性气体:NH3 ③中性气体:N2、O2、H2、CH4等 三、干燥剂的选择 1、总的原则:(酸碱性要一致且不能发生反应) a、酸性干燥剂不能干燥碱性气体,可以干燥酸性气体及中性气体; b、碱性干燥剂不能干燥酸性气体,可以干燥碱性气体及中性气体; c、中性干燥剂可以干燥各种气体。但这只是从酸碱反应这一角度来考虑, 2、同时还应考虑到规律之外的一些特殊性.如气体与干燥剂之间若发生了氧化还原反应,或生成络合物,加合物等,就不能用这种干燥剂来干燥该气体了。 特殊性: ①不能用浓硫酸干燥H2S, HBr,HI等还原性 ...气体,因为二者会发生氧化还原反应。如 H2S+H2SO4=2H2O+SO2+S↓,H2SO4+HBr= Br2+SO2+2H2O, H2SO4+HI= I2+SO2+2H2O ②不能用无水硫酸铜干燥H2S气体,二者会发生反应:CuSO4+H2S=H2SO4+CuS↓ ③不能用无水硫酸铜干燥NH3,二者可发生反应生成络合物:CuSO4+NH3={Cu(NH3)4}SO4 ④不能用无水CaCl2干燥NH3,二者会发生反应生成一些加合物:CaCl2+8NH3=CaCl2·8NH3

干燥剂的合理使用

干燥剂的合理使用 有机化合物在进行波普分析或定性、定量化学分析之前以及固体有机物在测定熔点前,都必须使它完全干燥,否则将会影响结果的准确性。液体有机物在蒸馏前也常要先进行干燥以除去水分,这样可以使液体沸点以前的馏分大大减少;有时也是为了破坏某些液体有机物与水生成的共沸化合物。另外很多有机化学反应需要在“绝对”无水条件下进行,不但所有的原料及溶剂要干燥,而且尚要防止空气中潮气浸入反应容器。因此在有机化学实验中,试剂和产品的干燥具有十分重要的意义。 一,基本原理 干燥方法大致可以分为物理法和化学法两种。物理法有吸附、分馏、利用共沸蒸馏将水分带走等方法。近年来还常用离子交换树脂和分子筛等来进行脱水干燥。化学法是以干燥剂来进行去水,其去水作用又可分为两类:(1)能与水可逆地结合生成水合物,如氯化钙、硫酸镁等;(2)与水发生不可逆的化学反应而生成一个新的化合物,如金属钠、五氧化二磷。目前应用最广泛的是第一类干燥剂。下面以无水硫酸镁为例讨论这类干燥剂的作用。 用无水硫酸镁来干燥含水的有机液体时,无论加入多少量的无水硫酸镁,在25℃时所能达到的最低水蒸气压力为1毫米汞柱,也就是说全部除去水分是不可能的。如加入的量过多,将会使有机液体的吸附损失更多;如加入的量不足,不能达到一水合物,则其蒸汽压力就要比1毫米汞柱高。这说明了在萃取时为什么一定要将水层尽可能分离干净,在蒸馏时为什么会有沸点前的馏分。通常这类干燥剂成为水合物需要一定的平衡时间,这就是液体有机物进行干燥时为什么要放置较久的道理。因为它吸收水分是可逆的,温度升高时蒸汽压也升高,因此液体有机物在进行蒸馏以前,必须将这类干燥剂滤除。 二,液体有机化合物的干燥 1.干燥剂的选择 液体有机化合物的干燥,通常是将干燥剂直接与之接触,因而使用的干燥剂必须不与该物质发生化学反应或催化作用,不溶解于该液体中。例如酸性物质不能用碱性干燥剂,碱性物质也不能用酸性干燥剂。有的干燥剂能与某些被干燥的物质生成络合物。如氯化钙易与醇类。胺类形成络合物,因而不能用来干燥这些液体。强碱性干燥剂如氧化钙、氢氧化钠能催化某些醛类或酮类发生缩合、自动氧化等反应,也能使脂类或酰胺类发生水解反应。氢氧化钾(钠)还能显著地溶解于低级醇中。在使用干燥剂时,还要考虑干燥剂的吸水容量和干燥性能。吸水容量是指单位重量干燥剂所吸得水量;干燥效能是指达到平衡是液体干燥的程度,对于形成水合物的无机盐干燥剂采用吸水后结晶水的蒸汽压来表示。例如,硫酸钠形成10个结晶水的水合物,其吸水容量达1.25.氯化钙再多能形成6个结晶水的水合物,其吸水容量为0.97。两者在25℃时水蒸气压分别为1.92及0.30毫米汞柱。因此,硫酸钠的吸水量较大,但干燥效能弱;而氯化钙的吸水量较小,但干燥效能强。所以在干燥含水量较多而又不易干燥的(含有亲水性基团)化合物时,常先用吸水量较大的干燥剂除去大部分水分,然后再用干燥效能强的干燥剂干燥。通常第二类干燥剂的干燥效能较第一类为高,但吸水容量较小,所以都是用第一类干燥剂干燥后,再用第二类干燥剂除去残留的微量水分,而且只是在需要彻底干燥的情况下才使用第二类干燥剂。此外选择干燥剂还要考虑干燥速度和价格。常用过自己的性能见表1: 表1各类有机物常用的干燥剂 化合物类型 干燥剂 烃 CaC12 、Na 、P2O5 卤代烃 CaC12、MgSO4 、、P2O5、Na2SO4 醇 K2CO3、MgSO4、CaO、Na2SO4 醚

高中化学常见干燥剂归纳

高中化学常见干燥剂归纳整理 1.高中化学常见的干燥剂有哪些 浓硫酸、五氧化二磷 固体烧碱、石灰和碱石灰(氢氧化钠和氧化钙的混合物)无水氯化钙、无水硫酸镁 无水硫酸铜 2.分类及使用 常用的干燥剂有三类 第一类为酸性干燥剂。有浓硫酸、五氧化二磷、硅胶等; 第二类为碱性干燥剂,有固体烧碱、石灰和碱石灰(氢氧化钠和氧化钙的混合物)等; 第三类是中性干燥剂,如无水氯化钙、无水硫酸镁等。 常用干燥剂的性能和用途如下: 1.浓H 2SO 4:具有强烈的吸水性,常用来除去不与H 2SO 4反应的气体中的水分。例如常作为H 2、O 2、CO 、SO 2、N 2、HCl 、CH 4、CO 2、Cl 2等气体的干燥剂。 2.无水氯化钙:因其价廉、干燥能力强而被广泛应用。干燥速度快,能再生,脱水温度473K 。一般用以填充干燥器和干燥塔,干燥药品和多种气体。不能用来干燥氨、酒精、胺、酰、酮、醛、酯等。

3.无水硫酸镁:有很强的干燥能力,吸水后生成MgSO 4·7H 2O 。吸水作用迅速,效率高,价廉,为一良好干燥剂。常用来干燥有机试剂。 4.固体氢氧化钠和碱石灰:吸水快、效率高、价格便宜,是极佳的干燥剂,但不能用以干燥酸性物质。常用来干燥氢气、氧气和甲烷等气体。 5.变色硅胶:常用来保持仪器、天平的干燥。吸水后变红。失效的硅胶可以经烘干再生后继续使用。可干燥胺、NH 3、 O 2、 N 2等。 6.活性氧化铝(Al 2O 3):吸水量大、干燥速度快,能再生(400 -500K 烘烤)。 7.无水硫酸钠:干燥温度必须控制在30℃以内,干燥性比无水硫酸镁差。 8.硫酸钙:可以干燥H 2 、O 2 、CO 2 、CO 、N 2 、Cl 2、HCl 、H 2S 、 NH 3、 CH4等。 注:无水硫酸铜(CuSO 4)(无水硫酸铜成白色)也具有一定的干燥性,并且吸水后变成蓝色的五水硫酸铜(CuSO 4·5H 2O ),但一般不用来做干燥剂。 3.干燥剂的选择 由上述可知、对一些气体的干燥剂可作如下选择。

干燥剂行业标准

干燥剂行业标准 青岛祥苑干燥剂有限公司1.范围 本标准规定包装用矿物干燥剂(一下简称“干燥剂”)的要求、实验方法及标志、包装、运输和储存。 2.成分/组成信息 二.化学分子式Mg5Si8O20(HO)2(OH2)4.4H2O 组成成分: 一.凹凸棒石粘土,膨润土,氯化钙 二.凹凸棒粘土主要氧化物含量: 三.凹凸棒石粘土卫生指标:mg/kg 砷(As)铅(Pb)汞(Hg)均没检出。 3.单位吸附能力 在25度---2度的气温条件下,一个单位质量的干燥剂吸附水蒸气的实际质量。 4. 要求 (1)单位吸附能力 通常情况下,单位吸附能力应为: a)3.00g(相当湿度为20%时)

b)6.00g(相当湿度为40%时) 5. 单位吸附速度 每袋规格大于16个单位的干燥剂7h吸附的水蒸气量应为:在相对湿度为40%时,吸附最小值为0.25g:在相对湿度为80%时,吸附最小值为0.70g。 6. 活化后吸附能力和速度 干燥剂活化后的吸附能力应维持原单位吸附能力的90%,吸附速度不低于原单位吸附速度的80%。 7. 腐蚀性 袋装干燥剂和干燥机本身与钢、黄铜、镁合金和铝合金接触时,应不产生腐蚀。 8. 实验方法 (1)单位吸附能力的测定 实验步骤:取一适合大小的干燥器,在器底放置一定量浓度的硫酸溶液,以便根据表1得到所要求的25度---2度下的相对湿度。 (2)吸湿率指标

9.标志、包装、储存和运输 (1)标志 (2)干燥剂包装袋上应清楚地标出所含干燥剂单位数量。 (3)包装箱上应标明:产品名称、生产厂名和地址、商标、生产标准、规格型号、数量、质量、生产日期及有效期。 (4)外包装收发货标志应符合有关规定,外包装储运图示标志应符合有关规定,使用“怕雨”“防潮”标志。 10. 包装 (1)干燥剂内包装袋选用具有透气性和一定强度的阻隔性复合材料,热合法制袋,封口粘合须严密牢靠。 (2)外包装选用瓦楞纸箱或纸桶或多层编织袋,应采用塑料薄膜进行密闭封装。 (3)每个外包装内应放使用说明书和产品合格证。 (4)包装袋所含干燥剂的单位数量应与一次使用的量相结合。 11. 储存和运输 (1)产品应保存在阴凉干燥且无化学污染的清洁库房内,不得受潮。不允许与易挥发物质长期储存在同一库房中。 (2)产品在运输过程中,应防止外包装破损,防治与酸、碱物质接触,避免雨淋。 12.技术指标

干燥剂用量的计算

干燥剂用量的计算 干燥剂用量的计算 -参照DIN55474标准 干燥剂用量是干燥剂应用中最关键的一点。如果干燥剂用少了,起不到有效防潮的作用, 产品会受到湿气的侵害;如果干燥剂用多了,则会产生浪费,不经济. □产品包装内目标湿度的设定 在开始计算干燥剂用量前,我们必须要设定一个目标湿度,即包装内允许的最高湿度。一般来说,普通产品在50%以下的湿度环境下就能安全保存,也有很多产品要求更低的湿度, 比如20%的环境。目标湿度设定越低,就需要用更多的干燥剂去保持包装内的干燥。 □阻隔包装的水汽透过率 水汽透过率是(克/平方米?以旨在一个稳定温度湿度条件下的静态环境中,经过24小时(天)的测试时间后渗透过测试材料的水蒸汽的克重。 阻隔包装物的水汽透过率对干燥剂用量的影响非常大,同样一个体积的包装要求保存相同 的时间,如果使用阻隔性很好的材料如铝箔,则干燥剂就可少用一点,如果使用阻隔性很差的材料如薄的PE袋,则需要放入很多的干燥剂才能起到同样的效果。 所以在条件允许的情况下,我们建议尽量采用阻隔性好(即水汽透过率低)的阻隔材料来包装产品。另外,阻隔包装的封口一定要严实,且绝对不可以有气孔,任何一个的微小的漏气孔都会使得干燥剂的效用大打折扣。 在不同的温度、湿度条件下,同一种阻隔材料的水汽透过率也是不同的。温度、湿度越高,水汽透过率也越高。但是我们在计算时候,只能取一个平均值来使用。DIN55474是建议我们使用 23C ,85%RH条件下的水汽透过率的值。如果结合实际情况取值会使计算更精确。 □包装中湿气的三个来源 在一个特定的包装中,湿气有三个来源,干燥剂的使命就是吸收这三部分水汽,将包装内的湿度控制在目标湿度之下。 (1)产品包装时候,包装内空气含有的初始湿气。比如产品包装的体积是1个立方, 包装时初始温度和湿度是23C ,85附目对湿度的时候,该空气中就含有17.47克水。 ⑵ 产品包装内的包装辅料所含的水分,在储藏运输过程中会逐步挥发出来。比如木料通常有15- 30%的含水率。 (3)在储藏运输过程中,通过阻隔包装物渗透到产品包装中的水汽。比如水汽透过

常用干燥剂个作用及原理

常用干燥剂个作用及原理 干燥剂是指能除去潮湿物质(固态、液态或气态)中水分子的物质。干燥剂根据其干燥原理可分为化学干燥剂和物理干燥剂两类。 一. 化学干燥剂 化学干燥剂是一些能吸收水分并常伴有化学反应的物质。常见的有:、浓、 等。 化学干燥剂的蒸气压比水蒸气的蒸气压要小,结果空气中或潮湿物质中的水蒸气不断凝聚进入干燥剂,并生成结晶水合物或相应的酸或碱。上述物质与水发生反应的方程式为: 碱石灰是另一例化学干燥剂,易吸收水份和,生成, ,既可以用作干燥剂又可以用作的吸收剂。 化学干燥剂的使用原则是,用于干燥气体的干燥剂不能与被干燥的气体发生反应。一般来说,酸性气体如等可以用酸性或中性干燥剂干燥,但不能用碱性干燥剂干燥;碱性气体如等可以用碱性或中性干燥剂干燥,但不能用酸性干燥剂干燥;中性气体如等用酸性、碱性或中性干燥剂干燥都可以;具有还原性的气体如等不能用浓硫酸等氧化性干燥剂干燥。同时,因能与发生氨合反应生成氨合物而不能用无水氯化钙干燥。常见干燥剂与应用如下表所示。 二. 物理干燥剂 能吸收水分但不伴有化学反应的干燥剂称为物理干燥剂。这类干燥剂常见的是硅胶。 硅胶又叫氧化硅胶和硅酸凝胶,化学式可用来表示。它是一种无色透明

或乳白色颗粒,一般约含水3%~7%,吸湿量可达40%。市售商品中常含有,称为变色硅胶。利用它在吸水和脱水中发生的颜色变化来指示硅胶吸湿程度。其过程可用下式表示: 硅胶作为干燥剂,其干燥原理是依靠吸附作用来除去潮湿物质中的水分子,即通过固体表面的质点与各种气体、液体等中的水分子发生相互吸引力而将其吸附在固体物质表面上。这类物质大多有很多的孔隙,有着巨大的表面积。 硅胶可用可溶性硅酸盐与盐酸反应而制得,反应的实际过程很复杂,反应方程式一般可 写为: 硅酸在水里的溶解度不大,但生成后并不立即沉淀,而是硅酸分子之间发生缩合形成硅酸凝胶。将硅酸凝胶充分洗涤除去可溶性盐类后,干燥脱水即成为多孔性固体物质,称为硅胶。 具有吸附作用能作为干燥剂的物理干燥剂,除了硅胶外,还有活性炭、活性氧化铝等。

美军标MIL-D-3464E-干燥剂、包装要求

MIL-D-3464E 21 April 1987 SUPERSEDING MIL-D-3464D 17 May 1966 (See 6-7) MILITARY SPECIFICATION DESICCANTS, ACTIVATED, BAGGED, PACKAGING USE AND STATIC DEHUMIDIFICATION This specification is approved for use by all Departments and Agencies of the Department of Defense. 1. SCOPE 1.1 Scope. This specification covers bagged, chemically inert, dehydrating agents that prevent corrosion and mildew by adsorbing the moisture from the air of an enclosed space. 1.2 Classification. The bagged desiccant shall be furnished in the following types, as specified (see 6.2): Type I General purpose. Type II Non-dusting. Type III For specific conditions (8 and 16 units only). 2. APPLICABLE DOCUMENTS 2.1 Government documents. 2.1.1 Specifications and standards. The following specifications and standards form a part of this specification to the extent specified herein. Unless otherwise specified, the issues of these documents shall be those listed in the issue of the Department of Defense Index of Specifications and Standards (DODISS) and the supplement thereto, cited in the solicitation. SPECIFICATIONS FEDERAL QQ-A-250/4 - Aluminum Alloy 2024, Plate and Sheet. QQ-B-637 - Brass, Naval: Rod, Wire, Shapes, Forgings, and Flat Products with Finished Edges (Bar, Flat Wire, and Strip). ú???????????????????????????????????????????????????????????????????????????????3Beneficial comments (recommendations, additions, deletions) and any pertinent 33data which may be of use in improving this document should be addressed to: 33Commander, Naval Sea Systems Command, SEA 55Z3, Department of the Navy, 33Washington, DC 20362-5101 by using the self-addressed Standardization Document33Improvement Proposal (DD Form 1426) appearing at the end of this document 33or by letter. 3à??????????????????????????????????????????????????????????????????????????????ù

有机常用干燥剂介绍.jsp

各类有机物常用干燥剂介绍 1,CaCL2,中性,与水作用产物:CaCL2.nH2O,n=1,2,4,6。适用范围:烃类,卤代烃,烯酮,醚,硝基化合物,中性气体,氯化氢。非适用范围:醇,胺,氨,酚,酯,酸,酰胺和某些醛酮。特点:吸水量大,作用快,效力不高,是良好的初步干燥剂。廉价,含有碱性杂质氢氧化钙。2,硫酸钠中性,与水作用产物:七水和十水硫酸钠。适用范围:醇,酯,醛,酮,酸,酰胺,卤代烃,硝基化合物等不能用氯化钙干燥的物质。吸水特点:吸水量大,作用慢,效力低,是良好的初步干燥剂。 3,硫酸镁中性,与水作用产物:一水和七水硫酸镁。适用范围:醇,酯,醛,酮,酸,酰胺,卤代烃,硝基化合物等不能用氯化钙干燥的物质。特点:较硫酸钠作用快,效力高。 4,硫酸钙中性,与水作用产物:CaSO4.1/2H2O,适用范围:烷,芳香烃,醚,醇,醛,酮。特点:吸水量小,作用快,效力高,可先用吸水量大的干燥剂初步干燥后再用。 5,碳酸钾碱性,与水作用产物:1.5水和2水合物。适用范围:醇,酮,脂,胺和杂环等碱性化合物,非适用范围:酸,酚及其他酸性化合物。 6,硫酸强酸性。与水作用产物:H3OSO4。适用范围:脂肪烃,烷基卤代物。非适用范围:烯,醚,醇及弱碱性化合物。特点:脱水效力高。 7,氢氧化钾,氢氧化钠强碱性。适用于胺,杂环等碱性化合物干燥。非适用于醇,酯,醛酮,酸,酚和酸性化合物干燥。其特点是干燥快速有效。 8,金属钠强碱性。适用于醚,三级胺,烃中的痕量水干燥。对碱土金属或对碱敏感物,醇等不适用。其特点是效力高,作用慢,需经初步干燥后才可再用,干燥后需蒸馏。 9,P2O5,酸性,适用于醚,烃,卤代烃,腈中痕量水分,酸溶液,二硫化碳。不适用于醇,酸,酮,胺,,碱性化合物,氯化氢,氟化氢等的干燥。其特点是吸水效力高,干燥后需蒸馏。10,CaH2,碱性,适用于碱性,中性,弱酸性化合物干燥,不适用于对碱敏感的化合物干燥。其特点是效力高,作用慢,先经初步干燥再用,干燥后需蒸馏。 11,CaO,Bao,碱性,适用于低级醇类,胺。其特点是效力高,作用慢,干燥后需蒸馏。 12,3A,4A分子筛,中性,是物理吸附,适用于各类有机物,不饱和烃气体。其特点是干燥快速高效,经初步干燥后可再用。 13,硅胶,常用于干燥器,不适用于氟化氢干燥。

常用固体液体干燥剂

实验室中常用的干燥剂及其特性 1、浓H2SO4:具有强烈的吸水性,常用来除去不与H2SO4反应的气体中的水分。例如常作为H 2、O2、CO、SO2、N2、HCl、CH4、CO2、Cl2等气体的干燥剂。 2、无水氯化钙(CaCl2):无定形颗粒状(或块状),价格便宜,吸水能力强,干燥速度较快,能再生,脱水温度473K。吸水后形成含不同结晶水的水合物CaCl2·nH2O(n=1,2,4,6)。最终吸水产物为CaCl2·6H2O (30℃以下),是实验室中常用的干燥剂之一。但是氯化钙能水解成Ca(OH)2 或Ca(OH)Cl ,因此不宜作为酸性物质或酸类的干燥剂。同时氯化钙易与醇类,胺类及某些醛、酮、酯形成分子络合物。如与乙醇生成CaCl2·4C2H5OH、与甲胺生成CaCl2·2CH3NH2,与丙酮生成CaCl2·2(CH3)2CO 等,因此不能作为上述各类有机物的干燥剂。不能用来干燥氨、酒精、胺、酰、酮、醛、酯等。 3、无水硫酸钠(Na2SO4):白色粉末状,吸水后形成带10个结晶水的硫酸钠 (Na2SO4·10H2O)。因其吸水容量大,且为中性盐,对酸性或碱性有机物都可适用,价格便宜,因此应用范围较广。但它与水作用较慢,干燥程度不高。当有机物中夹杂有大量水分时,常先用它来作初步干燥,除去大量水分,然后再用干燥效率高的干燥剂干燥。使用前最好先放在蒸发皿中小心烘炒,除去水分,然后再用。 4、无水硫酸镁(MgSO4):白色粉末状,吸水容量大,吸水后形成带不同数目结晶水的硫酸镁MgSO4·nH2O (n=1,2,4,5,6,7)。最终吸水产物为MgSO4·7H2O(48℃以下)。由于其吸水较快,且为中性化合物,对各种有机物均不起化学反应,故为常用干燥剂。特别是那些不能用无水氯化钙干燥的有机物常用它来干燥。 5、无水硫酸钙(CaSO4):白色粉末,吸水容量小,吸水后形成2CaSO4·H2O(100℃以下)。虽然硫酸钙为中性盐,不与有机化合物起反应,但因其吸水容量小,没有前述几种干燥剂应用广泛。由于硫酸钙吸水速度快,而且形成的结晶水合物在100℃以下较稳定,所以凡沸点在100℃以下的液体有机物,经无水硫酸钙干燥后,不必过滤就可以直接蒸馏。如甲醇、乙醇、乙醚、丙酮、乙醛、苯等,用无水硫酸钙脱水处理效果良好。 6、无水碳酸钾(K2CO3):白色粉末,是一种碱性干燥剂。其吸水能力中等,能形成带两个结晶水的碳酸钾(K2CO3·2H2O),但是与水作用较慢。适用于干燥醇、酯等中性有机物以及一般的碱性有机物如胺、生物碱等。但不能作为酸类、酚类或其他酸性物质的干燥剂。 7、固体氢氧化钠(NaOH)和氢氧化钾(KOH):白色颗粒状,是强碱性化合物。只适用于干燥碱性有机物如胺类等。因其碱性强,对某些有机物起催化反应,而且易潮解,故应用范围受到限制。不能用于干燥酸类、酚类、酯、酰胺类以及醛酮。 8、五氧化二磷(P2O5):是所有干燥剂中干燥效力最高的干燥剂。 P2O5与水作用非常快,但吸水后表面呈粘浆状,操作不便。且价格较贵。一般是先用其他干燥剂如无水硫酸镁或无水硫酸钠除去大部分水,残留的微量水分再用P2O5干燥。它可

固体药用纸袋装硅胶干燥剂06

固体药用纸袋装硅胶干燥剂06 1 国家药品监督管理局国家药品包装容器材料标准试行 YBB 固体药用纸袋 装硅胶干燥剂 Guti Yaoyong ZhiDaizhuang Guijiao Ganzaoji Desiccant for Oral Solid Preparation 本标准适用于固体制剂滤纸袋包装的细孔球型硅胶干燥剂。 【外观】取本品适量在自然光线明亮处正视目测。应纸面平整无明显色差包装袋各部位无破损。如有印刷需字迹清晰无污迹。【含水率】取样品适量规格3克/袋以下取2袋规格3克及3克以上/袋取1袋快速放入已干燥至恒重的称量瓶m1中精密称重m2将其放入150??5?烘箱内干燥4小时后精密称重m3按下式计算 m2-m3 含水率—————×100 m2-m1 不得过4.0。【吸湿率】取样品适量规格3克/ 袋以下取2袋规格3克及3克以上/袋取1袋平摊置于表面皿或适宜容器于150??5?烘箱内干燥2小时后取出置干燥器内冷却45分钟后取出快速精密称定m1平置放入恒温恒湿箱中同法操作另制备两份样品。三份样品分别置于温度均为25??2?相对 湿度分别为20?5、50?5、90?5条件下放置48小时取出快速精密称重m2。按下式 计算 m2-m1 吸湿率—————×100 m1 相对湿度20?5条件下吸湿率不得小于 7.0相对湿度50?5条件下吸湿率不得小于19.0相对湿度90?5条件下吸湿率不得 小于29.0 【抗跌性】取本品适量从1.2m高度自然跌落至水平刚性光滑表面不得破损。【纸袋的理化指标】纸袋荧光取样品10袋除去干燥剂将接触药物面的纸袋置于波长365nm和254nm 2 紫外灯下检查不得有片状荧光。砷取样品适量除 去干燥剂取纸袋2.00g置于坩埚中加1g氧化镁及10ml硝酸镁溶液混匀浸泡4小时。于低温或置水浴锅上蒸干用小火炭化至无烟后移入马弗炉中加热至550?灼烧34小时冷却后取出。加5ml水润湿后用细玻棒搅拌再用少量水洗下玻棒上附着的 灰分至坩埚内。放水浴上蒸干后移入马弗炉550?灰化2小时冷却后取出。加2ml

高中化学常用干燥剂

高中化学常用干燥剂有哪些? 1、浓H2SO4:具有强烈的吸水性,常用来除去不与H2SO4反应的气体中的水分。例如常作为H 2、O2、CO、SO2、N2、HCl、CH4、CO2、Cl2等气体的干燥剂。 2、无水氯化钙:因其价廉、干燥能力强而被广泛应用。干燥速度快,能再生,脱水温度473K。一般用以填充干燥器和干燥塔,干燥药品和多种气体。不能用来干燥氨、酒精、胺、酰、酮、醛、酯等。 3、无水硫酸镁:有很强的干燥能力,吸水后生成MgSO4.7H2O。吸水作用迅速,效率高,价廉,为一良好干燥剂。常用来干燥有机试剂。 4、固体氢氧化钠和碱石灰:吸水快、效率高、价格便宜,是极佳的干燥剂,但不能用以干燥酸性物质。常用来干燥氢气、氧气和甲烷等气体。 5、变色硅胶:常用来保持仪器、天平的干燥。吸水后变红。失效的硅胶可以经烘干再生后继续使用。可干燥胺、NH3、O2、N2等 6、活性氧化铝(Al2O3):吸水量大、干燥速度快,能再生(400 -500K烘烤)。 7、无水硫酸钠:干燥温度必须控制在30℃以内,干燥性比无水硫酸镁差。 8、硫酸钙:可以干燥H2 。O2 。CO2 。CO 、N2 。Cl2、HCl 、H2S、NH3、CH4等 1 实验室中常用的干燥剂及其特性 实验室中常用的干燥剂及其特性 ①无水氯化钙(CaCl2):无定形颗粒状(或块状),价格便宜,吸水能力强,干燥速度较快。吸水后形成含不同结晶水的水合物CaCl2·nH2O(n=1,2,4,6)。最终吸水产物为CaCl2·6H2O (30℃以下),是实验室中常用的干燥剂之一。但是氯化钙能水解成Ca(OH)2 或Ca(OH)Cl ,因此不宜作为酸性物质或酸类的干燥剂。同时氯化钙易与醇类,胺类及某些醛、酮、酯形成分子络合物。如与乙醇生成CaCl2·4C2H5OH、与甲胺生成CaCl2·2CH3NH2,与丙酮生成CaCl2·2(CH3)2CO 等,因此不能作为上述各类有机物的干燥剂。 ②无水硫酸钠(Na2SO4):白色粉末状,吸水后形成带10个结晶水的硫酸钠(Na2SO4·10H2O)。因其吸水容量大,且为中性盐,对酸性或碱性有机物都可适用,价格便宜,因此应用范围较广。但它与水作用较慢,干燥程度不高。当有机物中夹杂有大量水分时,常先用它来作初步干燥,除去大量水分,然后再用干燥效率高的干燥剂干燥。使用前最好先放在蒸发皿中小心烘炒,除去水分,然后再用。

如何测试干燥剂包装的透湿性能

如何测试干燥剂包装的透湿性能

摘要:干燥剂应具有及时吸附水蒸气的能力,这就要求包装干燥剂所用材料应具有较高的透湿性能。本文利用杯式法原理测试了干燥剂所使用的包装材料样品的水蒸气透过率,并通过对试验原理、设备W3/062水蒸气透过率测试系统的参数及适用范围、试验过程等内容的介绍,为如何监测干燥剂包装的透湿性能提供参考。 关键词:透湿性能、水蒸气透过率、水蒸气透过率测试仪、杯式法、称重法、增重法、减重法、干燥剂、包装材料 1、意义 干燥剂的种类较多,如氯化钙、五氧化二磷、硅胶、分子筛、蒙脱石等,可用于仪器仪表、电子产品、皮革、鞋、服装、食品、药品和家用电器等产品的干燥存储,以防止产品受潮或锈蚀。在干燥食品、药品等产品时,干燥剂需置于独立包装中,使其与内容物产品分开,如滤纸、无纺布、复合纸、网纹纸、蜡纸、杜邦纸等,见图1。由此可见,干燥剂并不是直接与待干燥环境中的水蒸气接触,水蒸气需要渗透到干燥剂的包装内部后方可被干燥剂吸收。因此,干燥剂的吸湿速率除了与干燥剂种类、尺寸等因素有关外,还取决于包装材料的透湿性能,良好的透湿性有助于干燥剂对水蒸气的快速吸收。本文针对性的测试了干燥剂所使用的包装材料的透湿性能。 图1 独立包装的干燥剂 2、试验样品 本文以某种干燥剂包装用透气膜为试验样品,测试其水蒸气透过率。 3、试验依据 包装材料水蒸气透过率的测试方法包括杯式法、红外传感器法、电解传感器法与湿度传感器法等,鉴于本文所测试样品的水蒸气透过率较高,故采用杯式法原理进行试验。

4、试验设备 本次试验采用W3/062 水蒸气透过率测试系统对样品进行测试,该设备由济南兰光机电技术有限公司自主研发生产。 图2 W3/062水蒸气透过率测试系统 4.1 试验原理 杯式法原理是通过称量透湿杯质量随渗透时间的变化情况得到试样的水蒸气透过率,根据透湿杯质量的增加或减轻,该原理又可分为增重法与减重法两种。增重法是指透湿杯内盛装一定量的干燥剂,装夹好试样后,透湿杯外侧为高湿环境,水蒸气从透湿杯外侧通过试样渗透到透湿杯内部,被干燥剂吸收,引起透湿杯质量增加;减重法是指透湿杯内部盛装一定量的蒸馏水,装夹好试样后,透湿杯外侧控制低湿环境,水蒸气由透湿杯内侧通过试样渗透到透湿杯外侧,引起透湿杯质量减轻。通过测试透湿杯的质量对渗透时间的变化情况,即可得到试样的水蒸气透过率。 4.2 适用范围 (1) 本设备适用于多种类型材料水蒸气透过率测试,如塑料薄膜、纸塑复合膜、土工膜、镀铝膜、铝塑复合膜、防水透气膜等膜状材料,PP片材、PVC片材、PVDC片材等工程塑料、橡胶、建材等片状材料,烟包铝箔纸、利乐包等纸张、纸板材料,防水透气布料、尿不湿无纺布料、卫生用品用无纺布等纺织品、无纺布等材料。除此之外,还可扩展应用于人造皮肤、医疗用品及辅料、太阳能背板、液晶显示屏膜、漆膜、化妆品、生物降解膜等材料及产品的透湿性、阻水性、保湿性测试。 (2) 本设备满足多项国家与国际标准,如GB 1037、GB/T 16928、ASTM E96、ASTM D1653、TAPPI T464、ISO 2528、DIN 53122-1、JIS Z0208、YBB 00092003等。 4.2 设备参数 可实现增重法与减重法两种试验模式,增重法测试范围为0.1 ~ 2,500 g/(m2·24h),减重法测试范围为

干燥剂

把干燥剂放在潮湿环境,让干燥剂快速吸湿,看干燥剂增加的重量有多少,识别干燥剂吸水性能来区分好坏。义乌玄德包装 可以做一个类比实验,实验装置很简单,在试管或者锥形瓶中加入定量的水,用胶塞和导管引出通过你要检验的干燥剂即可!试验完毕。只要称量各种干燥剂的质量对比原来多了多少? 这样就可以说明干燥剂的干燥能力。不过要注意的是:不能让所有的干燥剂都饱和就好! 所有加热蒸发水的时候要考虑一下应该加热多久还有就是干燥剂的质量! 医药保健品、生物试剂、食品行业专用干燥剂。专用干燥剂特点:卫生要求高,包装材料通过美国FDA论证,产品小巧高效、精致环保,有较好的相容性和化学稳定性。按应用环境区分,一般为三种情况: (1)在小环境中使用:干燥剂直接放在瓶、罐或其他密闭的小袋中,使小环境中的物品保持干燥。 (2)在中环境中使用:干燥剂直接放在包装的纸箱(或包装桶、袋)中使用,以避免包装中的物品受潮。 (3)在大环境中使用:干燥剂直接放在类似仓库、集装箱中使用,以达到控制大环境湿度的目的。词条图册 生石灰干燥剂-产品概况 生石灰干燥剂的主要成分为氧化钙,其吸水能力是通过化学反应来实现的,因此吸水具有不可逆性。不管外界环境湿度高低,本品能保持大于自重35%的吸湿能力,更适合于低温度保存,具有极好的干燥吸湿效果,而且价格较低。可广泛用于食品、服装、茶叶、皮革、制鞋、电器等行业。 生石灰干燥剂-相关指标 质量指标 吸湿率≥30% 颗粒度≥80% 氧化钙含量≥95% 包装规格

常用规格如下表所示(特殊规格可商定)单位:g/bag0.5g1g2g3g5g8g10g15g20g15g30g 40g50g80g100g150g200g250g300g400g500g1000g 包装材料 网纹纸、复合纸、复合无纺布、杜邦布等。 包装材料网纹纸强度标准如下:项目明细标准值 拉力强度竖向拉力强度(Kg)≥4.0 横向拉力强度(Kg)≥3.0 拉裂强度竖向拉裂强度(Kg)≥0.4 横向拉裂强度(Kg)≥0.4 破裂强度(Kg/cm2) ≥2.5 热接触强度(Kg)≥0.6 包装 内衬塑料袋封闭,外用瓦楞纸箱。 生石灰干燥剂-注意事项 该产品的包装材料,均采用无毒、无害材料。但该干燥剂严禁食用;若发生误食,请立即用水漱口 如果不小心进入眼睛,请迅速用水冲洗后找医生。禁止小孩玩耍。请勿放置在有水汽的地方。 产品运输过程中应避免受潮,包装箱应小心轻放,避免破损。 产品应储存在通风干燥的库房内,避免受潮。

德国包装干燥剂标准DIN55473概要

德国标准DIN55473概要 关于DIN55473和DIN认证 DIN55473是DIN(德国标准化学会)制定的用于规范工业用包装干燥剂的技术标准 德文原名: Packhifsmittel - Trockenmittelbeutel - Techniche Lieferbedingungen 英文译名: Auxiliary means of packaging - Desiccant Bag - Technical Delivery Conditions 中文译名:包装辅助手段- 袋装干燥剂- 技术交付条件 DIN 德国标准化学会 德文原名为Deutsches Institut für Normung, 是德国联邦政府承认的标准化主管机构,并代表德国参加非政府的区域性和国际标准机构,制定和发布德国标准及其他标准化成果并促进其应用。目前DIN制定的标准几乎涉及建筑工程、采矿、冶金、化工、电工、安全技术、环境保护、卫生、消防、运输、家政等各个领域。截至1998年底,共制定发布了2.5万个标准,每年大约制定1,500个标准。其中80%以上已为欧洲各国所采用。http://www.din.de DIN 认证 DIN认证工作由德国标准化学会(DIN)旗下的德国标准化学会认证中心(DIN CERTCO)负责。企业可以根据相应的DIN标准申请本企业的DIN认证,认证完毕合格的将颁发DIN认证证书并允许在产品上打上“DIN Geprüft”的标志。http://www.dincertco.de 用Unit单位来定义干燥剂的计量 有别于传统概念中比如“我需要6克干燥剂”的说法,在DIN55473标准中,用“单位”来定义干燥剂的计量,是按照实际使用功效的一种计量方法,更客观、更准确。 标准中规定:在(23±2)℃和40%相对湿度的空气中达到平衡时,吸收水汽至少能达到6.0g的指定数量的干燥剂为"一个单位"干燥剂。 对干燥剂产品的各技术指标、检验方法、包装要求都做出了详尽的规定 - 吸附剂的外观、PH值、电导率、水溶物含量、颗粒大小。 - 一个单位干燥剂的吸湿能力、体积、质量 - 干燥剂包装袋的防粉尘特性、强度、以及所包干燥剂的单位数。 DIN55473是如何规范干燥剂产品的? 标准规范了干燥吸附剂、单位干燥剂、干燥剂包装袋以及交付形式的各项技术指标。 干燥吸附剂 总要求: 颗粒,不含杂质不破碎 萃取液的PH值: 3.5-8 萃取液电导率: >=0.3 S/M 水溶物含量: <=2% 粒度: <6.3mm, >0.25mm(2%透过) 一个单位的干燥剂 吸湿能力: (23+-2°C, 40%), >=6克

常用干燥剂的性能和用途

常用干燥剂的性能和用途 1、浓H2SO4:具有强烈的吸水性,常用来除去不与H2SO4反应的气体中的水分。例如常作为H 2、O2、CO、SO2、N2、HCl、CH4、CO2、Cl2等气体的干燥剂。 2、无水氯化钙:因其价廉、干燥能力强而被广泛应用。干燥速度快,能再生,脱水温度473K。一般用以填充干燥器和干燥塔,干燥药品和多种气体。不能用来干燥氨、酒精、胺、酰、酮、醛、酯等。 3、无水硫酸镁:有很强的干燥能力,吸水后生成MgSO4.7H2O。吸水作用迅速,效率高,价廉,为一良好干燥剂。常用来干燥有机试剂。 4、固体氢氧化钠和碱石灰:吸水快、效率高、价格便宜,是极佳的干燥剂,但不能用以干燥酸性物质。党用来干燥氢气、氧气、氨和甲烷等气体。 5、变色硅胶:常用来保持仪器、天平的干燥。吸水后变红。失效的硅胶可以经烘干再生后继续使用。可干燥胺、NH3、O2、N2等。 6、活性氧化铝(Al2O3):吸水量大、干燥速度快,能再生(400 -500K烘烤)。 7、无水硫酸钠:干燥温度必须控制在30℃以内,干燥性比无水硫酸镁差。 8、硫酸钙:可以干燥H2。O2。CO2。CO 、N2。Cl2、HCl 、H2S、NH3、CH4等。 由上述可知、对一些气体的干燥剂可作如下选择。 气体名称常用干燥剂气体名称常用干燥剂 CO 浓H2SO4、CaCl2、P2O5H2S CaCl2 CO2CaCl2、浓H2SO4、P2O5N2浓H2SO4、CaCl2、P2O5 Cl2CaCl2、浓H2SO4NH3CaO、KOH或碱石灰 H2CaCl2、P2O5NO Ca(NO3)2 HBr CaBr2、ZnBr2O3CaCl2 HCl CaCl2、浓H2SO4SO2浓H2SO4、CaCl2、P2O5 HI CaI2 液体适用干燥剂 Drying Agents for Liquids

干燥剂使用大全

溶剂干燥方法 一些溶剂因为种种原因总是含有杂质,这些杂质如果对溶剂的使用目的没有什么影响的话,可直接使用。可是在进行化学实验和进行一些特殊的化学反应时,必须将杂质除去。虽然除去全部杂质是有困难的,但至少应该将杂质减少到对使用目的没有防碍的限度。除去杂质的操作称为溶剂的精制,故溶剂的精制几乎都要进行脱水,其次再除去其他的杂质。 1溶剂的脱水干燥: 溶剂中水的混入往往是由于在溶剂制造,处理或者由于副反应时作为副产物带入的,其次在保存的过程中吸潮也会混入水分。水的存在不仅对许多化学反应,就是对重结晶,萃取,洗涤等一系列的化学实验操作都会带来不良的影响。因此溶剂的脱水和干燥在化学实验中是很重要的,又是经常进行的操作步骤。尽管在除去溶剂中的其他杂质时有时往往加入水分,但在最好还是要进行脱水,干燥。精制后充分干燥的溶剂在保存过程中往往还必须加入适当的干燥剂,以防止溶剂吸潮。溶剂脱水的方法有下列几种: (1)干燥剂脱水 这是液体溶剂在常温下脱水干燥最常用使用的方法。干燥剂有固体,液体和气体,分为酸性物质,碱性物质,中性物质以及金属和金属氢化物。干燥剂的性质各有不同,在使用时要充分考虑干燥剂的特性和干燥剂的性质,才能有效达到干燥的目的。 在选择干燥剂时首先要确保进行干燥的物质与干燥剂不发生任何反应;干燥剂兼做催化剂时,应不使溶剂发生发生分解,聚合,并且干燥剂与溶剂之间不形成加合物。此外,还要考虑倒干燥速度,干燥效果和干燥剂的吸水量。在具体使用时,酸性物质的干燥最好选用酸性物质干燥剂,碱性物质的干燥用碱性干燥剂,中性物质的干燥用中性干燥剂。溶剂中有大量水存在的,应避免选用与水接触着火(如金属钠等)或者发热猛烈的干燥剂,可以先选用氯化钙一类缓和的干燥剂进行干燥脱水,使水分减少后再使用金属钠干燥。加入干燥剂后应搅拌,放置一夜。温度可以根据干燥剂的性质,对干燥速度的影响加以考虑。干燥剂的用量应稍有过剩。在水分多的情况下,干燥剂因吸水吸收水分发生部分或全部溶解生成液状或泥状分为两层,此时应进行分离并加入新的干燥剂。溶剂与干燥剂的分离一般采用倾析法,将残留物进行过滤,但过滤时间太长或周围的湿度过大会再次吸湿而使水分混入,因此,有时可采用与大气隔绝的特殊的过滤装置。有的干燥剂操作危险时,可在安全箱内进行。安全箱在置有干燥剂,使箱内充分干燥(我知道是无水五氧化二磷),或吹入干燥空气或氮气。使用分子筛或活性氧化铝等干燥剂时应添在玻璃管内,溶剂自上向下流动进行脱水,不与外界接触效果较好。大多数溶剂都可以用这种脱水方法,而且干燥剂还可以回收使用。 常用的干燥剂有: ①金属,金属氢化物 Al,Ca,Mg:常用于醇类溶剂的干燥 Na,K:适用于烃,醚,环己胺,液氨等溶剂的干燥。注意用于卤代烃时有爆炸危险,绝对不能使用。也不能用于干燥甲醇,酯,酸,酮,醛与某些胺等。醇中含有微量的水分可加入少量金属钠直接蒸馏。 CaH:一克氢化钙定量与0.85克水反应,因此比碱金属,五氧化二磷干燥效果好。适用于烃,卤代烃,醇,胺,醚等,特别是四氢呋喃等环醚,二甲亚碸,六甲基磷酰胺等溶剂的干燥。有机反应常用的极性非质子溶剂也是用此法进行干燥的。 LiAlH4:常用醚类等溶剂的干燥。 ②中性干燥剂 CaSO4,NaSO4,MgSO4:适用于烃,卤代烃,醚,酯,硝基甲烷,酰胺,腈等溶剂的干燥。CuSO4:无水硫酸铜为白色,含有5个分子的结晶水时变成蓝色,常用检测溶剂中微量水分。

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