JP3423365B2 - Composition for producing open-cell resin foam - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composition for producing an open-cell resin foam containing an olefin resin as a main component. [0002] Olefin-based resin foams have excellent properties such as heat insulation, cushioning, and sound insulation, and are used in the fields of packaging and packing, as well as for construction and automobiles. It is widely used in various fields. As the olefin-based resin foam, a closed-cell foam is mainly used, and thus cannot be used in application fields requiring water absorption, air permeability, and sound absorption. For this reason, the open-cell olefin resin foam for such application fields is manufactured by once producing a closed-cell foam using an olefin-based resin and then subjecting the cell wall to mechanical deformation to form the cell wall. Has been produced by a method of obtaining an open-cell foam by breaking the foam or further expanding the foam by heating expansion. However, in such a method, there are problems that the process has two steps and the obtained foam has a low open cell ratio, and only a product having insufficient water absorption and air permeability can be obtained. [0003] In order to solve this problem, a silicone compound such as silicone oil or silicone block copolymer is added to an ethylene resin to limit the decomposition temperature of a foaming agent and an organic peroxide. It is possible to manufacture an open-cell type ethylene-based resin foam without incorporating a separate process for foam breaking by, for example,
0-49657, Tokuhei 4-17219, Tokuhei 5
No. -5254. However, the silicone compounds used in the compositions used in these inventions, in particular, dimethyl silicone, which is generally widely known as silicone oil, has very poor compatibility with olefin resins, and is kneaded to form a composition. It was very difficult to knead it. [0004] When an open-cell olefin resin foam produced from the composition containing the silicone oil is used as a product, the compounded silicone compound easily bleeds out to the surface of the foam. In addition, there is a problem that adhesion and contamination are caused, and a problem that adhesion when foamed sheets are laminated is lowered. As a method for solving the problem of the bleed out of the silicone compound on the surface of the foam, Japanese Patent Application Laid-Open No.
In the inventions such as JP-A-223243 and JP-A-63-268748, a modified surfactant (silicone type) is added to the composition to be used, and JP-A-3-21641 and JP-A-3-21641 disclose the composition.
In the inventions of JP-A-269024, JP-A-3-269027, JP-A-3-287636, etc., a method in which a kneaded product of an ethylene-based resin and a silicone compound or a mixture is added to a composition to be used is proposed. However, any of these methods requires a special silicone compound or the kneading of the composition in two stages, which necessitates an increase in the cost of foam production, and furthermore, the silicone foam is obtained from the obtained foam. The effect of preventing the compound from bleeding out was not sufficient. SUMMARY OF THE INVENTION The present invention is directed to solving the problem of bleed-out of a silicone compound blended as a cell regulator, which is found in conventional open-cell olefin resin foams. As a result of repeated studies, the use of a specific mixture of olefin-based resins as the base resin allows the use of ordinary silicone oils without compounding special silicone compounds or kneaded products or mixtures of ethylene-based resins and silicone compounds. A composition capable of obtaining an open-cell olefin resin foam which does not cause bleed-out of the silicone oil over time by using as a cell regulator. That is, the composition for producing an open-cell resin foam of the present invention is ethylene-
1 to 30% by weight of a pyrolytic foaming agent with respect to 100 parts by weight of a resin comprising 30 to 90% by weight of a polar vinyl compound copolymer and 10 to 70% by weight of an ethylene-vinyl acetate-carbon monoxide terpolymer And 0.1 to 5 parts by weight of silicone oil. In the composition for producing an open-cell resin foam of the present invention, the ethylene-polar vinyl compound copolymer used as one component of the base resin includes, for example, saturated vinyl carboxylate such as vinyl acetate and vinyl propionate. A copolymer containing an unsaturated carboxylic acid ester such as methyl acrylate or ethyl acrylate; or a polar vinyl compound such as vinyl chloride in an amount of 5 to 50% by weight, preferably 10 to 30% by weight. Among them, preferred is an ethylene-vinyl acetate copolymer. Further, as the ethylene-vinyl acetate-carbon monoxide terpolymer used as another component of the base resin, when the content of carbon monoxide is within the range of 1.5 to 15% by weight, It is preferable that the content is in the range of 5 to 50% by weight. In the present invention, the reason that the mixing ratio of the ethylene-polar vinyl compound copolymer and the ethylene-vinyl acetate-carbon monoxide terpolymer is specified as 30 to 90:10 to 70 by weight ratio is as follows.
When the content of the ethylene-vinyl acetate-carbon monoxide terpolymer in the base resin composed of both is less than 30% by weight, open cells obtained from a composition in which silicone oil is blended as a foam control agent with this. This is because the mold resin foam has an insufficient effect of preventing bleed out of the silicone oil over time. In addition, ethylene in the base resin
If the amount of the vinyl acetate-carbon monoxide terpolymer exceeds 70% by weight, deacetic acid and coloring of the foam are liable to occur, and a high-quality open-cell resin foam cannot be obtained. It is. [0007] The foaming agent to be added to the composition includes, for example, azodicarbonamide, azobisisobutylnitrile, P-toluenebenzenesulfonylhydrazide, dinitrosopentamethylenetetramine and the like having a decomposition temperature of 100 to 170 ° C. A decomposition type foaming agent is used.
In particular, azodicarbonamide is preferred. The amount of the foaming agent is 1 to 30 parts by weight based on 100 parts by weight of the base resin.
The amount within the range of parts by weight is appropriate, and may be appropriately determined according to the desired expansion ratio. If the temperature range of the foaming agent is difficult to satisfy with a single foaming agent,
For example, a decomposition accelerator such as a urea compound, zinc oxide, or a zinc compound may be appropriately added. The silicone oil used in the present invention has a function as a cell regulator, and has the general formula: R ₃ SiO — (— R ₂ SiO) _n —SiR ₃ (R:
Unsubstituted or substituted monovalent hydrocarbon, n = 10 or more). If the amount of the silicone oil is less than 0.1 part by weight with respect to 100 parts by weight of the base resin, the foaming effect cannot be sufficiently exhibited. If the amount is more than 5 parts by weight, the effect is not increased and the cost is uneconomical, and the effect of preventing bleed out of silicone oil, which is the original object of the present invention, is impaired. Therefore, the amount of the silicone oil is desirably in the range of 0.1 to 5 parts by weight based on 100 parts by weight of the base resin. The composition of the present invention may optionally contain an organic peroxide. As the organic peroxide in this case, one having a one-minute half-life temperature of 150 to 200 ° C. is suitable. Examples of such an organic peroxide include t-butylperoxyisopropyl carbonate, dicumyl peroxide, and t-butylperoxyisopropyl carbonate. -Butyl cumyl peroxide. It is desirable that the compounding amount be 5 parts by weight or less based on 100 parts by weight of the base resin. Further, in the composition of the present invention, similarly to the conventional composition for producing an olefin-based resin foam, for the purpose of improving the properties of the obtained resin foam, various additives, additives, fillers, Specifically, an antioxidant, a coloring agent, an inorganic filler, a processing aid, a flame retardant, and the like can be appropriately compounded. The composition for producing an open-cell resin foam of the present invention is prepared by kneading the above components at a temperature lower than the decomposition temperature of a foaming agent or an organic peroxide to be used, using a Banbury mixer or a kneader. it can. Then, the prepared composition is formed into a desired shape such as a pellet, a powder, or a sheet, and then heated and foamed at a predetermined temperature to produce an open-cell resin foam having a desired shape. Hereinafter, the present invention will be described by way of examples. The open cell ratio of the open cell type resin foam is ASTM-D
It measured using the air comparison specific gravity meter (made by Toshiba Beckman) according to -2856. (Example 1) 70 parts by weight of an ethylene-vinyl acetate copolymer having a MFR of 14.0 g / 10 minutes and a vinyl acetate content of 15% by weight, and an MFR of 35 g / 10 minutes, a vinyl acetate content of 24% by weight and a carbon monoxide content of 10% by weight 30 parts by weight of ethylene-vinyl acetate-carbon monoxide terpolymer, 10 parts by weight of azodicarbonamide, and dimethyl silicone oil (3
000CS) 1 part by weight and zinc oxide 2 parts by weight were kneaded in a kneader having a capacity of 1 liter at 100 ° C. for 10 minutes, and then formed into a composition sheet having a thickness of 1 mm by a press forming machine at 100 ° C. Next, the obtained composition sheet was placed on a polyester film sheet, and heated and foamed in an air oven at 190 ° C. for 5 minutes to obtain a resin foam having open cells. The obtained resin foam has a thickness of about 15 m.
m, the density was 0.065 kg / m ³ , and the open cell ratio was 87%. The resin foam was allowed to stand at room temperature for one week. When the silicone foam was not peeled off from the polyester film sheet without bleeding out from the foam surface, the resin foam was broken. (Example 2) MFR 15.0 g / 10 minutes,
50 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 19% by weight and ethylene-vinyl acetate-carbon monoxide having an MFR of 35.0 g / 10 minutes, a vinyl acetate content of 24% by weight and a carbon monoxide content of 10% by weight. 50 parts by weight of a starting copolymer, 10 parts by weight of azodicarbonamide, 2 parts by weight of dimethyl silicone oil (3000CS), and zinc oxide 2
Parts by weight and 0.5 parts by weight of dicumyl peroxide
After kneading with an open roll at 90 ° C for 10 minutes,
The composition was formed into a composition sheet having a thickness of 1 mm by a press molding machine at a temperature of ℃. Next, the obtained composition sheet was placed on a polyester film sheet, and heated in an air oven at 190 ° C. for 5 minutes to foam, thereby obtaining a resin foam having open cells. The obtained resin foam had a thickness of about 15 mm and a density of 0.5.
At 050 kg / m ³ , the open cell ratio was 85%. The resin foam was allowed to stand at room temperature for one week. When the silicone foam was not peeled off from the polyester film sheet without bleeding out from the foam surface, the resin foam was broken. (Example 3) MFR 20.0 g / 10 minutes,
70 parts by weight of an ethylene-ethyl acrylate copolymer having an ethyl acrylate content of 20% by weight, and an MFR of 35.0 g / 1
0 minutes, vinyl acetate content 24% by weight, carbon monoxide content 10
30 parts by weight of an ethylene-vinyl acetate-carbon monoxide terpolymer of 10% by weight, 10 parts by weight of azodicarbonamide,
2 parts by weight of dimethyl silicone oil (3000CS) and 2 parts by weight of zinc oxide are kneaded in a 1-liter kneader at 90 ° C. for 10 minutes, and then formed into a 1 mm-thick composition sheet by a 100 ° C. press forming machine. did. Next, the obtained composition sheet was placed on a polyester film sheet, and heated in an air oven at 180 ° C. for 6 minutes to cause foaming, thereby obtaining a resin foam having open cells. The obtained resin foam had a thickness of about 15 mm and a density of 0.062 kg / m.
^{In 3} , the open cell rate was 82%. The resin foam was allowed to stand at room temperature for one week. When the silicone foam was not peeled off from the polyester film sheet without bleeding out from the foam surface, the resin foam was broken. (Comparative Example 1) MFR 15.0 g / 10 minutes,
100 parts by weight of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 19% by weight, 10 parts by weight of azodicarbonamide, 1 part by weight of dimethyl silicone oil (3000CS), 2 parts by weight of zinc oxide, and 0 parts of dicumyl peroxide 5 parts by weight at 90 ° C in a 1-liter kneader
And then kneaded for 10 minutes, and formed into a 1 mm-thick composition sheet with a press molding machine at 100 ° C. Next, the obtained composition sheet was placed on a polyester film sheet,
The mixture was heated and foamed in an air oven at 0 ° C. for 5 minutes to obtain a resin foam having open cells. The obtained resin foam had a thickness of about 15 mm, a density of 0.065 kg / m ³ and an open cell ratio of 85%. When this resin foam was left at room temperature for one week, bleed-out of silicone oil occurred on the foam surface, and the resin foam was easily peeled off from the polyester film sheet. Comparative Example 2 MFR 35.0 g / 10 minutes,
24% by weight of vinyl acetate, 10% by weight of carbon monoxide
Ethylene-vinyl acetate-carbon monoxide terpolymer 10
0 parts by weight, 10 parts by weight of azodicarbonamide, 2 parts by weight of dimethyl silicone oil (3000CS), and 2 parts by weight of zinc oxide are kneaded with an open roll at 80 ° C. for 10 minutes, and then pressed at 100 ° C. To form a composition sheet having a thickness of 1 mm. Next, the obtained composition sheet was placed on a polyester film sheet, and heated in an air oven at 190 ° C. for 5 minutes to foam, thereby obtaining a resin foam. The obtained resin foam was colored brown and had a bad acetic acid odor due to deacetic acid. As described above with reference to the Examples and Comparative Examples, according to the composition for producing an open-cell resin foam of the present invention, a special silicone compound or the like is foamed as in the prior art. It is possible to produce good open-cell resin foam of olefin resin by using ordinary silicone oil as a cell adjuster without using it as an adjuster, and this open-cell resin foam is capable of controlling cells over time. The silicone oil used as the agent does not bleed out from the surface of the foam.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ identification code FI C08L 83:04) (C08L 73/00 83:04) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 1 / 00-101/16 C08K 3/00-13/08 C08J 9/06

Claims (1)

(57) [Claims] [Claim 1] Ethylene-polar vinyl compound copolymer 3
With respect to 100 parts by weight of a resin consisting of 0 to 90% by weight and 10 to 70% by weight of an ethylene-vinyl acetate-carbon monoxide terpolymer, 1 to 30 parts by weight of a pyrolytic foaming agent and 0.1% of silicone oil are used. 1 to 5 parts by weight of a composition for producing an open-cell resin foam.