KR101075070B1 - Method preparing of the foam using composition using foam composition contain ethylene vinyl acetate resin and sillicone rubber - Google Patents

Abstract

The present invention relates to a method for producing a foam using the composition for producing a foam containing ethylene vinyl acetate resin and silicone rubber, specific gravity of the foam by mixing and foaming 31-50 parts by weight of silicone rubber with respect to 100 parts by weight of ethylene vinyl acetate resin. It has low mechanical properties such as tensile strength, tear strength and heat shrinkage, and has excellent permanent compressive shrinkage so that high elasticity can be maintained for a long time so that it can be widely applied to various applications such as not only for shoe midsole but also for building insulation. It is an advantage.

Ethylene Vinyl Acetate Resin, Silicone Rubber, Foam, Shoe Midsole

Description

Method for preparing foam using composition for preparing foam containing ethylene vinyl acetate resin and silicone rubber ethylene vinyl acetate resin and sillicone rubber

The present invention is foamed by using a foam composition containing ethylene vinyl acetate resin and silicone rubber, low specific gravity of the foam, mechanical properties such as tensile strength, tear strength and heat shrinkage rate is improved, and excellent permanent compression shrinkage It relates to a method for producing a foam using a composition for producing a foam containing ethylene vinyl acetate resin and silicone rubber, characterized in that to maintain a high elastic modulus to be used as a foam of various uses.

In general, ethylene vinyl acetate resin is rich in resilience elasticity, excellent in flex resistance, light weight, excellent weather resistance, and is widely used as a material of the foam. Synthetic rubber or natural rubber is mixed and foamed to produce a highly elastic foam, which is used for footwear midsoles and beach sandals.

Silicone rubber is a synthetic rubber made of cross-linked polymer reinforced with silica, and it retains its properties even at high heat, has superior tensile strength, elasticity and abrasion resistance than general organic rubber. Due to its excellent cold resistance, general organic rubbers are destroyed by impact at low temperatures, and there is almost no change in physical properties. Unlike other organic rubbers, silicone rubber has a double bond in the molecular structure that reacts with oxygen or ozone in the atmospheric layer to cause cracking. Because of its excellent weather resistance, there is almost no change in physical properties even when it is left outdoors, and it has excellent elasticity and resilience even in a wide temperature range up to 100 ~ 250 ℃ because of its excellent properties of permanent compression reduction. It is known as a material that is widely applied in the application fields of the required products.

By mixing and foaming a silicone rubber having such excellent physical properties with ethylene vinyl acetate resin, the mechanical properties and elasticity of the ethylene vinyl acetate foam can be improved, but the softening point of the ethylene vinyl acetate resin is 30 to 95 ° C, whereas the silicone rubber resin Since the softening point of 80 ~ 110 ℃ softening point is different from each other, it is difficult to mold the mixture of the resin, there was a limit to increase the mixing amount of the silicone rubber.

In view of the different softening points of ethylene vinyl acetate resin and silicone rubber, the present invention controls the processing temperature during kneading and foam molding of the mixed composition of ethylene vinyl acetate resin and silicone rubber, thereby producing a foam, thereby producing ethylene vinyl acetate resin. It is an object of the present invention to provide a method for producing a foam using a composition for preparing a foam containing an ethylene vinyl acetate resin and a silicone rubber, characterized in that the foam is mixed with 31 to 50 parts by weight of the silicone rubber with respect to 100 parts by weight.

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In the present invention for achieving the above object in the foam manufacturing method using a composition for producing a foam containing ethylene vinyl acetate resin and silicone rubber,
31 to 50 parts by weight of silicone rubber, 0.5 to 1.0 part by weight of zinc oxide as a metal oxide, 0.5 to 1.0 part by weight of stearic acid as a fatty acid, and a filler based on 100 parts by weight of ethylene vinyl acetate resin having a vinyl acetate content of 10 to 30% by weight. Put the ethylene vinyl acetate resin composition consisting of ~ 30 parts by weight in the kneader and kneaded at 100 ~ 130 ℃ for 30 to 40 minutes and then using the cooling water in the kneader with the temperature rise to 130 ℃ Gradually lowering the amount and then adding 4.0 to 10.0 parts by weight of the blowing agent at 120 ° C. and then lowering the temperature to 100 ° C. or lower to add 0.5 to 5.0 parts by weight of the crosslinking agent;
Kneading the ethylene vinyl acetate resin composition kneaded in the kneader using a mixing roller (Mixing Roller) for 10-15 minutes at 60 ~ 80 ℃;
Sheeting the finished ethylene vinyl acetate resin composition using a press;
The ethylene vinyl acetate resin composition sheet prepared above is cut to fit the size of a mold in a press, and the sheet is introduced to foam for 30 to 50 minutes under a temperature of 140 to 165 ° C. and a pressure of 130 to 150 kgf / cm 2. Step and;
Forming the foamed foamed product in a predetermined thickness and size, followed by trimming and grinding, and then molding the foamed molded product into a mold having a predetermined shape;
The manufacturing method of the foam using the composition for foam manufacturing containing ethylene vinyl acetate resin and silicone rubber which pass through is made into a problem solving means.

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The present invention by the above-mentioned solution means to foam by using a composition mixed with 31 parts by weight of silicone rubber with respect to 100 parts by weight of ethylene vinyl acetate resin, thereby improving mechanical properties such as hardness, tensile strength and tear strength of the foam It has a low permanent compression rate and is excellent in physical properties as a foam, so that it can be widely applied to various uses such as not only for shoe midsoles but also for building insulation.

The present invention for achieving the above effect relates to a method for producing a foam using a composition for producing a foam containing ethylene vinyl acetate resin and silicone rubber, only the parts necessary for understanding the technical configuration of the present invention will be described and other parts It should be noted that the description of will be omitted so as not to distract from the gist of the present invention.

Hereinafter, the technical configuration of the present invention will be described in detail.

The present invention provides a composition for producing a foam containing ethylene vinyl acetate resin and silicone rubber,

31 to 50 parts by weight of silicone rubber, 0.5 to 5.0 parts by weight of crosslinking agent, 4.0 to 10.0 parts by weight of foaming agent, 0.5 to 1.0 parts by weight of metal oxide, 0.5 to 1.0 parts by weight of fatty acid, filler 8 to 30 based on 100 parts by weight of ethylene vinyl acetate resin. It is characterized by consisting of parts by weight.

Ethylene vinyl acetate resin used in the present invention is rich in rebound elasticity, excellent in flex resistance and light, and excellent in physical properties such as hardness, tensile strength, and permanent compression shrinkage, and is widely used as a material for foams for shoe soles. The ethylene vinyl acetate resin is preferably a vinyl acetate content of 10 to 30% by weight.

The silicone rubber used in the present invention has superior tensile strength, elasticity and wear resistance characteristics than general organic rubber, in particular, excellent in cold resistance and weather resistance, and the amount of silicone rubber mixed with 100 parts by weight of ethylene vinyl acetate resin It is preferable that it is 31-50 weight part of rubber | gum.

When the amount of the silicone rubber is less than 31 parts by weight, the mechanical properties, the cold resistance and the weather resistance of the foam of the foam may decrease. When the amount of the silicone rubber is more than 50 parts by weight, the ethylene vinyl acetate resin and the silicone rubber Due to the difference in softening point, the foam may not be processed properly.

And it is preferable that the crosslinking agent used by this invention is 0.5-5.0 weight part with respect to 100 weight part of ethylene vinyl acetate resins. If the amount of the crosslinking agent is less than the amount of use, sufficient crosslinking may not be achieved. If the amount of the crosslinking agent is used, the physical properties of the foam may be lowered by overcrosslinking.

In addition, as the crosslinking agent usable in the present invention, dicumyl peroxide, benzol peroxide, ditetrabutyl peroxide, azodicarbonamide, t-butyl peroxy isopropyl carbonate, t-butyl peroxy laurate, t-butyl peroxide Oxycetate, di-t- butyl peroxy phthalate, t- dibutyl peroxy maleic acid, cyclohexanone peroxide, t-butyl cumyl peroxide, methyl ethyl ketone peroxide selected from 1 group It is preferable to use dicumyl peroxide more preferably.

And it is preferable to use 4.0-10.0 weight part with respect to the foaming agent used by this invention with respect to 100 weight part of ethylene vinyl acetate resins. If the amount of the blowing agent is less than 4.0 parts by weight, sufficient foaming is not achieved. If the amount of the blowing agent is more than 10.0 parts by weight, the foaming may be over-foamed and the mechanical properties may be lowered.

The blowing agents usable in the present invention are azodicarbonamides, diazominoexobenzenes, n, n'-dinitrosopentamethylenetetraamines, p-toluenesulfonylhydrazides, p, p'-oxy It is preferable to use one or more selected from the group consisting of a bis (benzenesulfonyl hydrazide) system or a benzenesulfonyl idraziad.

And the metal oxide used in the present invention is to promote crosslinking, it is preferable to add 0.5 to 1.0 parts by weight based on 100 parts by weight of ethylene vinyl acetate resin, when the amount of the metal oxide is out of the above range uncrosslinked or over There exists a possibility that the problem of bridge | crosslinking may arise.

The metal oxide usable in the present invention is preferably zinc oxide.

The fatty acids used in the present invention increase the dispersion effect of ethylene vinyl acetate resin, induce flat crosslinking, and act as a softener to facilitate processing, and the amount of fatty acids is 0.5 to 100 parts by weight of ethylene vinyl acetate resin. It is preferable that it is 1.0 weight part. When the amount of fatty acid is out of the above range, if the amount is small, it is difficult to control the crosslinking rate, and in many cases, there is a fear of blooming.

The fatty acid usable in the present invention is preferably stearic acid.

In addition, the filler used in the present invention can improve the shock absorbency of the foam and reduce the cost, but when used in excess, it may cause a problem in forming the foam as well as lowering durability. The amount of the filler to be used is preferably 8 to 30 parts by weight based on 100 parts by weight of ethylene vinyl acetate resin, and when the amount of the filler is less than 8 parts by weight, the filler does not exhibit a function as a filler, and the amount of the filler to exceed 30 parts by weight. In this case, it is difficult to control the foaming process, and thus there is a possibility that normal foam production is impossible.

The filler usable in the present invention is not particularly limited in its kind, but is mainly contained in clay, mica, hard coal, magnesium carbonate, calcium carbonate, silicic anhydride, hydrous silicic acid, calcium silicate, aluminum silicate, high styrene resin, coumarone indene resin, and talc. It is preferable to select and use 1 type or more.

Hereinafter, a method of manufacturing a foam using the composition for preparing a foam containing ethylene vinyl acetate and silicone rubber according to the present invention is as follows.

The present invention is a method for producing a foam using a composition for producing a foam containing ethylene vinyl acetate resin and silicone rubber,

Ethylene vinyl acetate resin composition excluding the blowing agent and the crosslinking agent is placed in a kneader and kneaded sufficiently, followed by adding a blowing agent and a crosslinking agent;

Performing a Soviet operation of the kneaded ethylene vinyl acetate resin composition in a kneader using a mixing roller;

Sheeting the finished ethylene vinyl acetate resin composition using a press;

Cutting the ethylene vinyl acetate resin composition sheet prepared above according to the size of a mold in a press to insert the sheet and foaming the sheet;

Forming the foamed foamed product in a predetermined thickness and size, followed by trimming and grinding, and then molding the foamed molded product into a mold having a predetermined shape;

Through this, a foam containing ethylene vinyl acetate resin and silicone rubber is produced.

In the kneading step, the ethylene vinyl acetate resin composition ('ethylene vinyl acetate resin composition' means a composition composed mainly of ethylene vinyl acetate resin and silicone rubber) except for a blowing agent and a crosslinking agent is added to a kneader. Knead it. The kneading conditions are preferably kneaded at 100 to 130 ° C. for 30 to 40 minutes.

At this time, the temperature of the kneader is raised to 130 ° C. and then the temperature is gradually lowered by using the cooling water in the kneader. Then, the blowing agent is added at 120 ° C. and then lowered to 100 ° C. or lower to add the crosslinking agent. If the foaming agent is added at a temperature of 130 ° C. or higher, the foaming agent may cause premature foaming due to heat in the kneader. If the crosslinking agent is added at a temperature of 100 ° C. or higher, the desired product may not be obtained due to premature foaming. After the crosslinking agent is added to the kneader, it usually does not exceed 5 minutes, and early foaming may occur. Normal time is about 30-40 minutes.

At the Soviet stage, the kneaded ethylene vinyl acetate resin composition is used for the Soviet Union using a Mixing Roller. At this time, the temperature of the roller must be maintained at 60 to 80 ° C. Difficult time adjustment can cause problems in producing uniform products. In addition, if it is less than 60 ℃ physical mixing is not performed. It usually takes about 10-15 minutes.

In the sheeting step, the ethylene vinyl acetate resin composition should be put into a press for sheeting. In general, the sheet that has been completely cooled after sheeting is put into the press in a general foam manufacturing process or sheeting operation. By inserting the semi-cooled (sheet temperature 30 ~ 40 ℃) sheet into the press using a cooling fan, the press working time can be shortened by 5 ~ 10 minutes, and the sheet is automatically cooled and semi-cooled at the same time. It prevents sticking between sheets in overlapping sheets, so it is easy to apply press afterwards.

In the foaming step, a sheet suitable for the size of a mold in the press is introduced. The press is heated at a temperature of 140 to 165 ° C. and a pressure of 130 to 150 kgf / cm 2 for 30 to 50 minutes. If the temperature is less than 150 ℃ foaming and crosslinking does not occur normally, if the temperature is 170 ℃ or more, the desired foam can not be obtained due to the phenomenon such as tearing of the product by over-crosslinking. In addition, if the time is less than 30 minutes, it is difficult to obtain the foam by the non-crosslinking, and if it exceeds 50 minutes, the phenomena such as tearing due to the overcrosslinking occur.

Foam produced through the above process has a low specific gravity of the foam, improved mechanical properties such as tensile strength, tear strength and heat shrinkage rate, and excellent compression compression rate to maintain high elasticity for long In addition, it is a feature that can be widely applied to a variety of applications, such as building insulation.

Hereinafter, the configuration of the present invention will be described in more detail based on the following examples, but the present invention is not necessarily limited only to the following examples.

1. Preparation of molded foam articles containing ethylene vinyl acetate resin and silicone rubber

(Examples 1 to 3 and Comparative Example 1)

Using the ethylene vinyl acetate resin composition having the components and components of [Table 1] below, a foam containing ethylene vinyl acetate and silicone rubber was prepared according to the following method.

Using the ethylene vinyl acetate resin composition shown in Table 1 below, first, the ethylene vinyl acetate resin composition except for the blowing agent and the crosslinking agent was added to the kneader, and then kneaded to 130 ° C. first, and then the cooling water was turned on to turn the temperature to 120 ° C. After lowering to add a blowing agent, and further cooled to lower the temperature to 100 ℃ and add a crosslinking agent. Two minutes after the crosslinking agent is added, it is taken out of the kneader, and the Soviet work is carried out for 10 to 15 minutes at 70 ℃ on a roller. After the sheeting operation, press-molded for 40 minutes under foaming conditions of a temperature range of 155 ° C. and a pressure range of 150 kgf / cm 2 to prepare a foam having a desired shape, and then put it in a mold having a square shape and press it at a high temperature at 155 ° C. for 10 minutes. After cooling, the mold was closed for 10 minutes at a low temperature of 20 ° C., and the product was demolded to prepare a foam molded article.

                                                            (Unit: parts by weight) Ingredient Example Comparative example One 2 3 One Suzy EVA resin ^{1 )} 100 100 100 100 Silicone rubber resin ^{2 )} 30 40 50 - additive Crosslinking agent ^{3 )} 0.5 2.5 5.0 2.0 Foaming agent ^{4 )} 4.0 8.0 10.0 6.0 Metal oxides ^{5 )} 0.7 0.7 0.7 0.7 Fatty acid ^{6 )} 0.7 0.7 0.7 0.7 Filler-1 ⁷⁾ 5 5 5 5 Filler-2 ⁸⁾ 5 5 - -

Note 1) Vinyl acetate content 22% by weight

   2) HR1941 (HRS)

   3) Dicumyl peroxide

   4) Azodicarbonamide type JTR (Gumyang)

   5) Zinc Oxide (SBC Chemical)

          6) stearic acid

          7) magnesium carbonate

          8) Calcium Carbonate

2. Evaluation of foam molded articles containing ethylene vinyl acetate and silicone rubber

As a result of evaluating the physical properties such as hardness, specific gravity, tensile strength, tear strength, etc. of the molded article of the ethylene vinyl acetate foam of Examples 1 to 3 and Comparative Example 1 prepared by the method of the above 1 Same as the content.

Test Items Example Comparative example One 2 3 One Longitude (C-type) 54 55 54 55 importance 0.18 0.17 0.18 0.22 Tensile strength (kgf / cm ² ) 30.1 36.2 39.6 21.2 Tear strength (kgf / cm) 13.2 15.4 20.1 8.4 Permanent Compression Decrease (%) 46.3 40.2 34.1 50.1 Heat shrinkage (%) 1.0 1.0 0.5 3.5 Rupture Tear Strength (kgf / cm) 1.5 1.9 2.0 1.1

As shown in Table 2, the molded articles containing the ethylene vinyl acetate and silicone rubber of Examples 1 to 3 are lighter than the molded articles of Comparative Example 1, and have physical properties such as tensile strength, tear strength, and heat shrinkage. All were found to be excellent.

And in Example 3, the silicone rubber was mixed up to 50 parts by weight, it was confirmed that the physical properties such as heat shrinkage, including tensile strength, compared to the molded products of Examples 1 and 2 more excellent.

Therefore, the composition for preparing a foam containing the ethylene vinyl acetate resin and the silicone rubber of Examples 1 to 3 according to the present invention has improved mechanical properties such as tensile strength and tear strength of the foam as shown in [Table 2]. It is expected to be widely applied to various applications such as not only for shoe midsoles but also for building insulation as it has excellent physical properties as a foam due to its low permanent compression rate.

As described above, the composition for producing a foam containing the ethylene vinyl acetate resin and the silicone rubber according to the present invention has been confirmed its superiority through the above examples, and the present invention is claimed by those skilled in the art to the following claims It will be understood that various modifications and changes can be made in the present invention without departing from the spirit and scope of the invention as set forth in the following.

Claims (8)

delete delete delete In the manufacturing method of the foam using the composition for foam manufacture containing ethylene vinyl acetate resin and silicone rubber, 31 to 50 parts by weight of silicone rubber, 0.5 to 1.0 part by weight of zinc oxide as a metal oxide, 0.5 to 1.0 part by weight of stearic acid as a fatty acid, and a filler based on 100 parts by weight of ethylene vinyl acetate resin having a vinyl acetate content of 10 to 30% by weight. Put the ethylene vinyl acetate resin composition consisting of ~ 30 parts by weight in the kneader and kneaded at 100 ~ 130 ℃ for 30 to 40 minutes and then using the cooling water in the kneader with the temperature rise to 130 ℃ Gradually lowering the amount and then adding 4.0 to 10.0 parts by weight of the blowing agent at 120 ° C. and then lowering the temperature to 100 ° C. or lower to add 0.5 to 5.0 parts by weight of the crosslinking agent; Kneading the ethylene vinyl acetate resin composition kneaded in the kneader using a mixing roller (Mixing Roller) for 10-15 minutes at 60 ~ 80 ℃; Sheeting the finished ethylene vinyl acetate resin composition using a press; The ethylene vinyl acetate resin composition sheet prepared above is cut to fit the size of a mold in a press, and the sheet is introduced to foam for 30 to 50 minutes under a temperature of 140 to 165 ° C. and a pressure of 130 to 150 kgf / cm 2. Step and; Forming the foamed foamed product in a predetermined thickness and size, followed by trimming and grinding, and then molding the foamed molded product into a mold having a predetermined shape; Method for producing a foam using the composition for producing a foam containing ethylene vinyl acetate resin and silicone rubber, characterized in that through. delete delete delete delete