LY/T 1738-2020Plywood for parquet (English PDF)

5.1 Specification size deviation

The specification and size deviation of the plywood for solid wood composite floor shall meet the requirements of Table 1.

5.2 Appearance quality

The appearance quality of the plywood for solid wood composite floor should meet the requirements of Table 2.

5.3 Physical and chemical properties

The physical and chemical properties of the plywood for solid wood composite flooring should meet the requirements of Table 3.

6.1 Determination of size deviation

6.1.1 Length, width and thickness deviation

According to the provisions of GB/T 19367-2009 in 8.2 and 8.1.

6.1.2 Verticality and edge straightness

According to GB/T 19367-2009 in 8.3 and 8.4.

6.1.3 Warpage

According to the provisions of GB/T 19367-2009 in 8.5.

6.2 Determination of appearance quality

Carry out according to the provisions of 6.3.1 in GB/T 9846-2015.

6.3 Determination of physical and chemical properties

6.3.1 Method of sawing specimens and test pieces

6.3.1.1 Take three sets of 500mm×500mm samples from each plywood for solid wood composite flooring for testing, if the test panel is not enough Take 3 sets of samples at a time, which can be selected from two plates.

6.3.1.2 The preparation position, size and quantity of the test piece shall be carried out in accordance with Table 4 and Figure 1.The length and width of the test piece should be perpendicular to each other, the size error Must not exceed ±0.5mm.

6.3.1.3 When samples and test pieces are intercepted, material defects and processing defects that affect the accuracy of the test shall be avoided.

6.3.1.4 The formaldehyde emission sample can be taken separately, with a total surface area of 1m2.

6.3.1.5 If the size of the sample cannot meet the requirements of the sample preparation, the number of samples may be increased.

6.3.2 Water content

According to the provisions of 4.3 in GB/T 17657-2013.

6.3.3 Dimensional stability

According to GB/T 17657-2013 4.33 length change rate measurement regulations, of which 6 longitudinal and transverse specimens each, divided into two groups for adjustment Wet treatment.

6.3.4 Dip peeling

Type I plywood shall be carried out according to the provisions of 4.19.4.1a) in GB/T 17657-2013, and type II plywood shall be carried out according to GB/T 18103-2013 in 6.3.2.

6.3.5 Bending strength and elastic modulus

According to GB/T 17657-2013, 4.7, the test piece needs to be balanced.

6.3.6 Formaldehyde emission

Carry out according to the regulations of formaldehyde emission determination in GB 18580.

7.1 Inspection classification

7.1.1 Product inspection is divided into factory inspection and type inspection.

7.1.2 The factory inspection shall include the following items.

a) Specification and size deviation;

b) Appearance quality;

c) Water content and immersion peeling items in physical and chemical properties.

7.1.3 Type inspection includes all inspection items in specification and size deviation inspection, appearance quality inspection and physical and chemical properties. In the following situations Temporarily, type inspection should be carried out.

a) When the raw and auxiliary materials and production process undergo major changes;

b) When production resumes after a long-term shutdown;

c) During normal production, the inspection should be no less than twice a year;

d) When the quality supervision department requests inspection.

7.2 Sampling method and determination principle

7.2.1 Appearance quality inspection

Adopt the one-shot sampling plan with the general inspection level in GB/T 2828.1-2012 as II and the acceptance quality limit (AQL) as 4.0, which should meet

Table 5 stipulates.

7.2.2 Inspection of size deviation

Adopt a single sampling plan with a special inspection level of S-4 and an acceptance quality limit (AQL) of 6.5 in GB/T 2828.1-2012.

Comply with Table 6.

7.2.3 Physical and chemical performance inspection

7.2.3.1 Samples should be randomly selected from products stored for more than 72 hours after production. The sampling number of physical and chemical properties should meet the requirements of Table 7.

7.2.3.2 Judgment rules for physical and chemical properties

The arithmetic average of water content, static bending strength and elastic modulus in the physical and chemical performance indicators meets the requirements specified in 5.3, then the water content, static bending the strength and elastic modulus are judged as qualified, otherwise it is judged as unqualified.

In the physical and chemical performance index, if all the specimens of immersion peeling meet the requirements specified in 5.3, the immersion peeling is judged as qualified, otherwise it is judged as unqualified.

In the physical and chemical performance indicators, the length of the longitudinal and transverse specimens with dimensional stability and relative humidity from 65% to 30% under the two sets of humidity conditioning treatments the arithmetic average of relative change (shrinkage rate and expansion rate) and relative change in length (shrinkage rate and expansion rate) when the relative humidity is from 85% to 65% all values meet the requirements specified in 5.3, the dimensional stability is judged as qualified, otherwise it is judged as unqualified.

The determination of formaldehyde emission is carried out in accordance with GB 18580.

In the physical and chemical performance test, if an indicator is unqualified in the initial inspection result, the indicator is allowed to be re-inspected once. When re-inspection, in the same batch the number of samples in the product is doubled to re-inspect the unqualified items. If the re-inspection is qualified, it is judged as qualified, otherwise it is judged as unqualified.

7.3 Comprehensive judgment

When the size deviation, appearance quality and physical and chemical properties of the product meet the corresponding requirements, the batch of products is judged to be qualified; otherwise, it is judged as Unqualified.

8.1 Identification

The product or packaging should be marked. manufacturer's name, address, product name, trademark, executive standard number, specification, category, grade, glue Type of adhesive, formaldehyde emission label, number of sheets, production date, etc.

8.2 Packaging

When leaving the factory, it must be packaged separately according to different categories, specifications, grades, and batch numbers to prevent the board surface from being stained.

8.3 Transportation and storage

The products should be stacked flat during transportation and storage to prevent contamination, and should not be exposed to damp, rain or insolation.

During storage, they should be stacked separately according to category and specifications, and each stack should be marked accordingly.