gb 5048- 1999
damp-proof packing
damp-proof packing
Replace gb/t 5048- 1985.
1 range
This standard specifies the moisture-proof grade, requirements, packaging methods, test methods and marks of packaging.
This standard is applicable to industrial products such as machinery and electronics, and other products can also be used for reference.
2 reference standard
The clauses contained in the following standards constitute the clauses of this standard by reference in this standard. At the time of publication of this standard, all versions shown are valid. All standards will be revised, and all parties using this standard should explore the possibility of using the latest version of the following standards.
Gb191-1990 graphic signs for packaging, storage and transportation.
Test method for water vapor permeability of plastic films and sheets
Gb/t 698 1- 1986 test method for moisture permeability of rigid packaging containers
Test method for moisture permeability of flexible packaging containers
Gb/t 10455- 1989 silica gel desiccant for packaging
Gb/t 12339- 1990 protective inner packaging materials.
Gb/t15171-1994 test method for sealing performance of flexible packaging.
Gjb 145a- 1993 Specification for Protective Packaging
Gjb 2494- 1995 Specification for Humidity Indicator Card
Gjb 27 14- 1996 General specification for static moisture-absorbing bagged active desiccant for packaging.
3 Moisture-proof packaging grade
3. 1 When the product needs moisture-proof packaging, the moisture-proof packaging grade requirements of the product packaging must be specified in the product technical documents.
3.2 The moisture-proof grade of packaging should be determined according to the nature of products, circulation environment, storage and transportation time, general performance of packaging containers and other factors.
3.3 Moisture-proof packaging is divided into 1 packaging, 2-packaging and 3-packaging. See table 1 for details.
Table 1 Moisture-proof packaging grade
Seek achievement
Moisture-proof period, temperature and humidity conditions, product characteristics
1 grade packaging 1~2 years, the temperature is more than 30℃, the relative humidity is more than 90%, it is sensitive to humidity, easy to rust, mold and deteriorate, and it is a precious and precise product.
The second kind of packaging is slightly sensitive to humidity, more expensive and more accurate. The temperature is 20~30℃, and the relative humidity is 70%~90%, 0.5~ 1 year.
Grade 3 covers products that are insensitive to humidity with a temperature less than 20℃ and a relative humidity less than 70% within 0.5 years.
4 requirements
4. 1 General requirements
4. 1. 1 Determine the moisture-proof packaging grade and package according to the grade requirements.
4. 1.2 products must be dry and clean before packaging.
4. 1.3 When the product has sharp protrusions which may damage the moistureproof layer, protective measures should be taken.
4. 1.4 When products need other protection requirements while being moisture-proof, corresponding measures should be taken according to the provisions of other professional packaging standards.
4. 1.5 Support and fix to prevent the product from moving during transportation. Should be placed as far as possible outside the moisture barrier. .
4. 1.6 The volume of moisture-proof packaging should be reduced.
4. 1.7 humidity indicator card, humidity indicator or humidity indicator device shall be used, and it shall be far away from desiccant. The humidity indicator card shall comply with the relevant provisions of gjb 2494.
4. 1.8 moisture-proof packaging should be connected at one time. If the operation is stopped halfway, temporary moisture-proof protection measures should be taken.
4.2 Humidity requirements in moisture-proof packaging
During the validity period of moisture-proof packaging, the relative humidity of the air in the packaging container shall not exceed 60%(25℃).
4.3 Material requirements
4.3. 1 The quality of materials selected for moisture-proof packaging must comply with the provisions of relevant product standards.
4.3.2 The selection of moisture-proof internal protective packaging materials shall comply with the relevant provisions of gb/t 12339.
4.3.3 Moisture permeability of moisture-proof packaging materials or packaging containers shall be selected according to the level of moisture-proof packaging in Table 2. The water vapor permeability of the material shall comply with the relevant provisions of gb/t 1037. The moisture permeability of hard packaging containers should comply with the relevant provisions of gb/t 698 1. The moisture permeability of flexible packaging containers should comply with the relevant provisions of gb/t 6982.
Table 2 Moisture permeability of moisture-proof packaging materials and containers
Moisture-proof packaging grade
Film, g/(m2 for 24 hours)
Container 1) g/(30m 2)
1 packaging
& lt2
& lt five
Secondary packaging
& lt five
& lt 120
Level 3 packaging
& lt 15
& lt450
1) was measured at a temperature of (40 1)℃ and a relative humidity of 80%~92%.
4.3.4 All packaging materials should be dry, and the cushioning and padding materials should not absorb moisture or have low moisture absorption.
4.4 desiccant requirements
desiccant
Unless otherwise specified, the desiccant is generally silica gel or montmorillonite, and the silica gel desiccant shall comply with the relevant provisions of gb/t 10455. Montmorillonite desiccant should meet the requirements of gjb 27 14.
Placement of desiccant
The desiccant should be put into a cloth bag or paper bag with sufficient strength and placed in the most suitable position of the packaging container. The mouth of desiccant bag should be fastened with string, and the hanging bag should be fixed by other methods. Prevent the bag from moving or breaking to damage the product. The desiccant bag shall not contact with the precise surface of the product; When it comes into contact with parts coated with antirust agent, the bag and product should be separated by non-corrosive and oil-resistant packaging materials; The time from taking out the treated desiccant to putting it in a package and sealing it should be as short as possible.
Selection of desiccant
The selection of desiccant can be made according to Appendix A. ..
4.5 Sealing requirements
4.5. 1 The sealing and heat sealing strength of moisture-proof packaging shall be tested according to the provisions of 6. 1 and shall be greater than 30n/5cm.
4.5.2 The sealing performance of moisture-proof flexible packaging shall be tested according to the provisions of 6.2, and there shall be no defects such as pinholes, cracks and unsealing.
4.6 Environmental requirements
The packaging environment should be clean and dry. The temperature shall not be higher than 35℃ and the relative humidity shall not be higher than 75%; No condensation is allowed.
5 Moisture-proof packaging method
5. 1 Use metal or nonmetal containers with zero or near zero moisture permeability to package products and seal them:
A) Packaging without desiccant: vacuum packaging, inflatable packaging, etc.
B) Packaging with desiccant: generally, silica gel and montmorillonite are selected as desiccant.
5.2 Use flexible materials with low water vapor permeability, package products with desiccant and seal:
A) packaging a single flexible film with a desiccant;
B) packaging the composite membrane with a desiccant;
C) Multilayer packaging, which uses different materials with low water vapor permeability.
6 test method
6. 1 The sealing strength test shall be conducted according to the heat sealing test in gjb 145a.
6.2 The sealing performance test of flexible packaging and moisture-proof packaging shall conform to gb/t 15 17 1.
6.3 The performance test of moisture-proof packaging shall be conducted in accordance with the provisions of gjb 145a on periodic exposure test. 1 optional test b of packaging. For Category 2 and Category 3 packaging, test A is optional. After the test, the relative humidity of the air in the package meets the requirements of 4.2.
Seven signs
The moisture-proof mark of the package shall be marked on the outside of the package according to the provisions of gb 19 1.
Appendix a
(Appendix of Prompt)
Selection of desiccant
A 1 selection of general desiccant
Simple calculation and selected dosage of general desiccant are calculated according to formula (a 1):
w =……………………………………(a 1)
Where: w-desiccant dosage, g;
Moisture absorption coefficient of k- desiccant [k = kb/ka]. Ka is the moisture absorption rate of fine hollow silica gel at 25℃ and 60% relative humidity, which is 30%; Kb is the moisture absorption rate of other desiccants (such as molecular sieve, alumina, activated clay, etc.). ) under the same temperature and humidity conditions. When fine silica gel is used, k =1];
V —— internal volume of packaging container, dm3 (value).
Selection of a2 Silica Gel Desiccant
A2. 1 dosage of silica gel desiccant:
The dosage of fine pore silica gel is calculated according to formulas (a2), (a3), (a4) and (a5):
Metal containers sealed by mechanical methods;
w = 20+v+ 0.5d(a2)
Aluminum-plastic composite bag:
w = 100 ay+0.5d(a3)
Bags made of plastic film packaging materials such as polyethylene;
w = 100 ar 1y+0.5d……………………………………(a4)
Seal cans and plastic cans with sealant tape:
w = 300 r2y+0.5d(a5)
Where: w-desiccant dosage, g;
V —— internal volume of packaging container, dm3 (value);
D —— Quality of wet materials (wrapping paper, cushion, cushioning material, etc.). ) in the bag, g;
A —— the total area of packaging materials, m2 (value);
Y —— planned storage time (take the time of next desiccant replacement), a;
R 1 —— water vapor permeability of packaging film material at 40℃ and 90% relative humidity, g/(m2 24h);
R2 refers to the water vapor permeability of sealed cans and plastic cans with sealing tape at 40℃ and relative humidity of 90%, g/(m2.24h);
A2.2 The water vapor permeability of composite materials consists of the water vapor permeability of each layer. Usually, it takes the sum of the reciprocal of water vapor permeability (r 1, r2...rn) as the reciprocal of its water vapor permeability (r).
Namely:
………………………………(a6)
A2.3 The storage time in formulas (a3), (a4) and (a5) refers to the storage time under severe weather conditions (temperature and humidity). If it is necessary to convert the storage time under different climatic conditions, it can be done according to the provisions in Appendix B and Appendix C of gjb 145a- 1993.
Selection of a3 Montmorillonite Desiccant
The selected dosage of montmorillonite desiccant is calculated according to formulas (a7) and (a8):
Sealed hard metal packaging container
u = kv+x 1d+x2d+X3D+x4d……………………(a7)
Sealed packaging containers other than hard metal packaging containers
u = ca+x 1d+x2d+X3D+x4d……………………(A8)
Where: U refers to the unit quantity consumed by desiccant, and 1 unit desiccant can absorb at least 3g (20% r h) or 6g (40% r h) of water vapor at the equilibrium temperature of 25℃;
K- coefficient, when the internal volume of the packaging container is given in cubic meters, take 42.7;
V —— internal volume of packaging container, m3 (value);
C —— coefficient, when the inner surface area of the damp-proof cover is in square meters, it is taken as17.2;
A —— internal surface area of packing box, m2 (value);
X 1- coefficient, when the padding is fiber material (including wood) and other materials not listed in the following classification, take17.64;
X2 —— coefficient, which is 7.92 when the filler is bonded fiberboard;
X3 —— coefficient when the filler is glass fiber, 4.41;
X4-coefficient, when the filler is foamed plastic or rubber, take1.11;
D-mass of filler, kg (value).