JPS5841310B2 - Synthetic resin composition for tarpaulin film formation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to so-called tarpaulins made of various textiles and the like with a flexible synthetic resin coating formed on one or both sides thereof, and to improvements in the synthetic resin composition used for the coating. It is.

Tarpaulin is widely used as an industrial material in various fields, and the composite resin material that forms its coating is
Generally, soft vinyl chloride resin formulations are most commonly used.

However, soft vinyl chloride resin formulations, along with the plasticizers they contain to make them soft, are considered unsuitable in fields that require complete non-toxicity, and are currently being used as processed tarpaulins. In addition, problems such as oozing of the plasticizer or transfer of the plasticizer to articles in contact occur.

For this reason, the film-form synthetic resin used for this type of application is ethylene-vinyl acetate copolymer resin (hereinafter referred to as EV), which is non-toxic and does not require a plasticizer, instead of vinyl chloride resin.
(referred to as A resin) has been used.

Although this EVA resin does not have the disadvantages of the above-mentioned vinyl chloride resin blend coating, it does have the following disadvantages.

■ Lack of flexibility makes handling difficult.

■ Poor heat resistance, poor temperature dependence such as adhesion and strength loss at high temperatures.

■ Poor wear resistance, easily causing scratches and breakage.

■ Poor high-frequency weldability, resulting in poor workability during molding.

In addition, in order to improve the disadvantages of using EVA resin, for example, EVA resin with a high vinyl acetate content is used to maintain flexibility, and the heat resistance that is lowered due to this is reduced by using ethylene propylene copolymer or ethylene. - By blending a certain amount of propylene-diene terpolymer to supplement it, or by adding a certain amount to EVA resin, chlorinated polyethylene improves flexibility and acrylonitrile-containing butadiene rubber improves high-frequency weldability. Although some research has been done on the former, high frequency weldability has not been improved and static electricity has been generated more easily, causing problems in practical use.In the latter, high frequency weldability has not been improved and the film strength has been reduced. There are drawbacks such as a decrease in abrasion resistance and welder strength, and the current situation is that it has not reached the level of comprehensive improvement.

In order to completely improve these conventional drawbacks, the present invention
A synthetic resin composition is provided by mixing appropriate amounts of a thermoplastic polyurethane resin and an ethylene-vinyl acetate vinyl chloride terpolymer into an ethylene-vinyl acetate copolymer resin.

Hereinafter, the synthetic resin composite acid of the present invention will be explained in detail.

The composite resin composite of the present invention is first made by mixing a thermoplastic polyurethane resin and an ethylene-vinyl acetate-hinyl chloride terpolymer at a certain ratio to form, for example, pellets, which are then made from EVA resin. It is blended and kneaded.

Therefore, the mixing ratio of the thermoplastic polyurethane resin and the ethylene vinyl acetate-vinyl chloride terpolymer is 70 to 70%.
range force of 30-10% by weight of the latter for 90% by weight;
If the latter exceeds 30%, the final product mixed with EVA resin will become too hard and the coating strength will also decrease.

Moreover, when the latter is less than 10% by weight, the compatibility of the EVA resin becomes poor and blending becomes difficult.

Therefore, it is best to use a mixture of 80% by weight of thermoplastic polyurethane resin and 20% by weight of ethylene-vinyl acetate-vinyl chloride terpolymer.

(Hereinafter, this compound will be tentatively referred to as modified polyurethane).

Next, the EVA resin and this modified polyurethane are mixed to obtain the resin composition of the present invention, and the mixing ratio is in the range of 50 to 10% by weight of the modified polyurethane to 50 to 90% by weight of the EVA resin. For example, in the case of a flexible container that is used in large quantities among tarpaulins, a blend ratio of 90% by weight of a flexible container made of tarpaulin using only EVA resin and 10% by weight of modified polyurethane is suitable.

Next, the results of a comparison between an example of a tarpaulin using the resin composition of the present invention and a tarpaulin made of EVA resin alone under the same conditions will be described.

(Hereinafter, the mixing ratio indicates weight percentage).

The resin composition of the present invention was kneaded in the proportions shown in the examples, and this was formed into a film using a calendar roll, and the base material was made of polyester (ioo).

This film was laminated and integrated on both sides of a plain weave fabric of 16 denier x 17 strands/inch) to make a tarpaulin with a thickness of 1 inch, which was used as a sample.

(Hereinafter referred to as sample A).

On the other hand, as a comparison sample, Evaflex P-1905 (manufactured by Mitsui Polychemical Co., Ltd.) (ethylene vinyl acetate copolymer) was coated with 0.4% processing aid and an appropriate amount of colorant using a calendar roll. A tarpaulin with a thickness of 11nrIL was prepared and used as a sample.

(hereinafter referred to as sample B). The properties of each material used in the above sample are as follows.

□ The following describes the results of various performance measurements of samples A and H using the above materials.

・About high-frequency weldability High-frequency weldability is the process of fusing resins by high-frequency heating, and the difficulty lies in numerically determining the high-frequency weldability of the resin composition by measuring the dielectric loss factor. You can judge the difficulty level.

Therefore, dielectric loss factor - dielectric constant (ε) x dielectric loss tangent (tan δ)
Therefore, it can be calculated by measuring the dielectric constant and dielectric loss tangent.

The measured numbers are shown in the table below.

That is, the dielectric loss factor of Sample A (made of the resin composition of the present invention) is improved by about twice that of Sample B (made of EVA alone), indicating that the high frequency weldability is much better. .

- Regarding welder strength, the results of measuring the strength when tarpaulin samples were joined by a high-frequency welder are shown in the following table, and the results made of the resin composition of the present invention are clearly superior to those made of EVA alone.

In the table above, the high frequency welder conditions are manufactured by Sansui Beater,
The output 2 was W, the frequency was 40.68 MH2, the time was 5 seconds, the pressure was 17 kg/cyA, the anode current was 0.7 A, the sample fusion area was 2o, 6c=, and the measurement temperature was 20°C.

- Abrasion resistance As shown in the following table, the abrasion resistance of the resin composition of the present invention is greatly improved compared to that of EVA alone.

Measurement conditions are JISK-69 using a taper abrasion tester.
Ring C8-17, load 1kg, rotation speed 1 by 02 method
It was set as 000.

・Retention of flexibility Regarding retention of flexibility, the hardness at each ambient temperature was measured by torsional rigidity, and as shown in the following table, the standard temperature 2
The resin composition of the present invention is more flexible at 0°C, and the resin composition of the present invention maintains more flexibility than the EVA resin alone up to a temperature as low as -20°C.

On the other hand, when the ambient temperature is 40 to 80 degrees Celsius, the EV
If resin A is used alone, it will become extremely soft, and its tackiness, tensile strength, and creep resistance will decrease, resulting in practical problems when the tarpaulin is used in a flexible container, but the resin composition of the present invention In the case of a solid material, the degree of softening is small and it can withstand practical use.

Torsional rigidity (according to ASTM D 1043 method) ・Regarding temperature dependence, resin compositions for tarpaulin require appropriate flexibility, but if this becomes excessive and the strength decreases, it will cause problems, so thermoplastic resins as the main When doing so, changes in the atmospheric temperature, especially when the temperature rises, become a problem, but A.
As a result of comparing the temperature dependence of sample B by tensile strength,
As shown in FIG. 1, the resin composition of the present invention has E.
The temperature dependence in a part of the welder is superior to that made of VA resin alone.

In the figure, the welding conditions are 5 seconds, pressure 17 and 9.
/cra, and the current is 0.7 A.

As mentioned above, the synthetic resin composition according to the present invention is characterized by mixing certain amounts of a thermoplastic polyurethane resin and an ethylene-vinyl acetate-vinyl chloride terpolymer into an ethylene-vinyl acetate copolymer resin. Therefore, it is a non-toxic and non-plasticizing agent, and when used as a tarpaulin, for example, in a flexible container, it can be used in conventional EVs.
This product has the excellent properties described above and can be widely used as an industrial material by improving the various drawbacks of products made of A resin alone and products similar thereto.

[Brief explanation of the drawing]

The drawing is a diagram showing a comparison of the temperature dependence of a weld part of a tarpaulin made of the synthetic resin composition of the present invention and that of an EVA resin alone.

Claims (1)

[Claims] 1 70 to 90% by weight of thermoplastic polyurethane resin and ethylene-vinyl acetate-vinyl chloride terpolymer: 30 to 90% by weight
A resin blend obtained by mixing 10% by weight of the ethylene-vinyl acetate copolymer resin is mixed with 50% to 90% by weight of the ethylene-vinyl acetate copolymer resin.
1. A tarpaulin-coated composite resin composition for military use, characterized in that it is mixed at a ratio of ~10% by weight.