Electronic Industrial Standards of the People's Republic of China
General Specification for Static-Free Turnover Containers
1 Scope
1.1 Subject content
This specification contains definitions, requirements, test methods, quality assessment procedure and mark, packaging, transportation and storage of the thermoplastic, thermosetting conductive (static-free) plastic materials and static dissipative plastic materials as well as various static-free turnover containers processed or assembled by injection molding and thermal forming (hereafter referred to as turnover containers).
1.2 Applicable scope
This specification applies to the development, production and delivery of the turnover containers for electronic products.
2 Quoted standards
The clauses in the following standards constitute the clauses of this specification by being referenced by this specification. When this specification is published, the versions as shown are valid. All standards will be amended. All parties that use this specification shall discuss the possibility of using the latest version of the following standards.
GB 1410-89 Test Method for Volume Resistivity and Surface Resistivity of Solid Electric Insulated Materials
GB 11210-89 Resistance Measurement of Vulcanized Rubber Static-Free and Conductive Products
3 Definition
3.1 Decay time of charge
The time it takes that the electrostatic potential produced by the turnover container materials as per the specified conditions decays to 10% of the starting point.
4 Classification and naming
4.1 Classification
4.1.1 Category of turnover containers
Turnover containers are divided into three categories by their structure and usage way:
a. Component case (pan);
b. Turnover case;
c. Fixed and mobile turnover shelf.
4.1.2 Type of turnover containers
Turnover containers are divided into three types by their static protection capabilities:
a. Static shielding type;
b. Conductive (static) type;
c. Static dissipative type.
5. Requirement
5.1 Appearance quality
Surface of the turnover containers should be smooth, level, free of cracks and bubbles. But small blackspots caused by slight ripples and release agent are allowed.
5.2 Dimension
Comply with the design drawing.
5.3 Antistatic property
5.3.1 Surface resistivityρs and volume resistivity ρv
a. Static shielding type
ρs≤1×103Ω and ρv≤1×102Ω.cm
b. Conductive (static) type
ρs＜1×105Ω and ρv＜1×104Ω.cm
c. Static dissipative type
1×105Ω≤ρs≤1×109Ω及1×104Ω.cm≤ρv≤1×108Ω.cm.
5.3.2 Surface resistance evenness
Make sampling inspection from the same batch of the same kind of products and classify the surface resistance value evenness of 3-5 parts of different parts of the sampled products into class A, B and C.
Class A: The surface resistance value index gap measured of the same product is in one order of magnitude, i.e. the value difference is no more than 101.
Class B: The surface resistance value index gap measured of the same product is in two orders of magnitude, i.e. the value difference is no more than 102.
Class C: The surface resistance value index gap measured of the same product is in more than two orders of magnitude, i.e. the value difference is more than 102.
5.3.3 Decay time of charge
Test the turnover container material sample as specified in 6.4.2.2. For the decay time of charge, the static dissipative type shall not exceed 10.0s and the conductive (static) type shall not exceed 2.0s.
6.4 Antistatic property inspection
6.4.1 Specimen preparation
Directly test on the sample or take sample as per 6.2. Take three squares with the length of side of 100mm.
6.4.2 Detection process
6.4.2.1 Resistivity
Surface resistivity shall be tested as per GB 11210 and volume resistivity shall be tested as per GB 1410. For materials of static shielding and conductive (static) turnover containers, the test voltage is 10v; for materials of static dissipative turnover containers, the test voltage is 100v. The test result shall correspond with the requirement in 5.3.1.
6.4.2.2 Decay time of charge
When measuring, place the specimen on the test baseplate of the static decay tester. After the test baseplate is charged to ±1000v, the time that the specimen takes to discharge to the ground by earthing plate to ±100V is the decay time of charge, which shall comply with 5.3.3.
8.3 Transportation
The packaged products can be transported by any transportation tools. However, they shall be protected from rain, sun exposure, contamination, heavy load and damage.
8.4 Storage
The packaged products shall be placed in a well-ventilated environment with a temperature of －5℃～40℃ and relative humidity of no more than 85%. Its distance from heat source should be no less than 2m.
8.5 Shelf life
From the date of shipment, the shelf life of the products stored under specified conditions shall be no less than one year.