foam

Abstract

The present invention provides a foam that has a low environmental impact and contains many interconnected pores, resulting in a high recovery rate between the thickness of the intermediate foam before defoaming and the thickness of the foam after defoaming and restoration treatment, making it suitable for use as a sealing material for air conditioners and the like. [Solution] A foam obtained by foaming a foamable resin composition containing a bioresin made of biopolyethylene and / or bioethylene vinyl acetate copolymer, a crosslinking agent and a crosslinking aid, wherein the content of the crosslinking agent in the foamable resin composition is 0.60 parts by weight or more and 0.90 parts by weight or less per 100 parts by weight of the bioresin, and the content of the crosslinking aid is 0.05 parts by weight or more and 0.30 parts by weight or less per 100 parts by weight of the bioresin.

Description

Technical Field

[0001] The present invention relates to a foam obtained by foaming a foaming resin composition containing a bio resin as a raw material. Specifically, since the foam uses a bio resin as a raw material, it has a low environmental load, and since it contains many communication holes, the restoration rate of the thickness of the foam after defoaming treatment and restoration treatment is high with respect to the thickness of the intermediate foam before defoaming. <00OOOO8>

Background Art

[0002] > Generally, the method of manufacturing a foam by in-mold molding is to knead a resin composition and a foaming agent while heating, fill the kneaded foaming resin composition into a mold and press it to crosslink the foaming resin composition, and then open the press to foam the foaming resin composition.

[0003] The manufactured foam can be compressed with a roll or the like to form ventilation holes by destroying the bubble film, or to form communication holes by connecting independent holes.

[0004] When there are many communication holes, the foam has excellent resilience.

[0005] On the other hand, in order to reduce the environmental load, a foam using a bio resin as a raw material is required.

[0006] However, since the crosslinking speed of bio resin is different from that of resins using general petroleum as a raw material, gas leakage occurs with the crosslinking agent used for conventional resins, and the place where gas leakage occurs shrinks, so there is a problem that the yield rate decreases.

[0007] In addition, there is a problem that independent holes are likely to occur and it is difficult to form communication holes even after defoaming treatment.

[0008] If the foam does not contain many communication holes, the restoration rate of the foam decreases.

[0009] There is a problem that a foam with a low restoration rate cannot be used as a sealing material for an air conditioner or the like.

[0010] Therefore, there is a need for the development of an environmentally friendly foam made from bio-resin, containing many interconnected pores, exhibiting excellent recovery properties, and suitable for use as a sealing material in air conditioners and other applications. [Prior art documents] [Patent Documents]

[0011] [Patent Document 1] Japanese Patent Publication No. 2012-246437 [Overview of the project] [Problems that the invention aims to solve]

[0012] Patent Document 1 describes a resin composition for foam molding and a foam that can be obtained that has a high closed-cell ratio, appropriate rigidity, and biodegradability.

[0013] However, the foam described in Patent Document 1 has rigidity, but it has few interconnections and poor resilience, which means it cannot be used as a sealing material for air conditioners and the like.

[0014] The inventors, with the technical challenge of solving the aforementioned problems, conducted numerous prototypes and experiments through trial and error, and have now found a foam obtained by foaming a foamable resin composition containing a bioresin made of biopolyethylene and / or bioethylene vinyl acetate copolymer, a crosslinking agent and a crosslinking aid, wherein the content of the crosslinking agent in the foamable resin composition is the bioresin 1 A remarkable finding has been obtained that a foam containing 0.60 parts by weight or more and 0.90 parts by weight or less of the crosslinking aid per 00 parts by weight of the bio-resin, and with a crosslinking aid content of 0.05 parts by weight or more and 0.30 parts by weight or less per 100 parts by weight of the bio-resin, is suitable for use as a sealing material for air conditioners and the like, due to its low environmental impact and high recovery rate because it contains many interconnecting pores, thus solving the aforementioned technical problem. [Means for solving the problem]

[0015] The aforementioned technical problems can be solved by the present invention as follows.

[0016] The present invention relates to a foam obtained by foaming a foamable resin composition containing a bioresin made of biopolyethylene and / or bioethylene vinyl acetate copolymer, a crosslinking agent, and a crosslinking aid, wherein the content of the crosslinking agent in the foamable resin composition is 0.60 parts by weight or more and 0.90 parts by weight or less per 100 parts by weight of the bioresin, and the content of the crosslinking aid is 0.05 parts by weight or more and 0.30 parts by weight or less per 100 parts by weight of the bioresin.

[0017] Furthermore, the present invention relates to the foam in which the crosslinking agent is dicumyl peroxide and the crosslinking aid is triallyl isocyanurate.

[0018] Furthermore, the present invention relates to a foam in which the thickness of the intermediate foam obtained by foaming the foamed resin composition is restored by a restoration process after the intermediate foam has been defoamed, and the restoration rate of the thickness of the foam is 80% or more.

[0019] The present invention also relates to a method for producing the foam, wherein the intermediate foam is a foam produced by heating the foamable resin composition at 120°C or higher and 140°C or lower for 60 minutes or more and 80 minutes or less, and then heating the intermediate product at 160°C or higher and 165°C or lower to produce foam, and the restored foam is a foam produced by defoaming treatment followed by a restoration treatment by heating at 60°C or higher and 80°C or lower for 2 hours. [Effects of the Invention]

[0020] The foam used in this invention is made from bio-resin, and therefore has a low environmental impact when disposed of.

[0021] Furthermore, because the present invention creates many interconnected pores through degassing treatment, the foam has a high recovery rate after restoration treatment, making it suitable for use as a sealing material for air conditioners and the like.

Mode for Carrying Out the Invention

[0022] The foam in the present invention is made from a bioresin composed of biopolyethylene and / or a bioethylene vinyl acetate copolymer produced using plants as raw materials.

[0023] SEB853 (manufactured by Braskem) is exemplified as the biopolyethylene.

[0024] Braskem SVT2180 (19%) (manufactured by Braskem) is exemplified as the bioethylene vinyl acetate copolymer. <00​​​​​​​​​​​​​​​​​​​​​​​The crosslinking agent is not particularly limited, but examples include dicumyl peroxide, 1,1-dittery butyl peroxide, 1,1-dittery butyl peroxy-3,3,5-trimethylcyclohexane, 2,5-dimethyl-2,5-dittery butyl peroxyhexane, 2,5-dimethyl-2,5-dittery butyl peroxyhexine, α,α-dittery butyl peroxyisopropylbenzene, tert-butyl peroxyketone, and tert-butyl peroxybenzoate.

[0031] The foamed resin composition in this invention includes a crosslinking aid to adjust the crosslinking rate.

[0032] Adding a crosslinking aid increases the initial crosslinking rate, making it easier to retain the bubbles generated by foaming and reducing gas leakage.

[0033] The content of the crosslinking aid in the foamed resin composition is preferably 0.05 to 0.30 parts by weight, and more preferably 0.1 to 0.2 parts by weight.

[0034] If the amount of crosslinking aid is less than 0.05 parts by weight, initial crosslinking may not proceed, potentially leading to gas leakage. If it exceeds 0.30 parts by weight, the bubbles may become smaller, reducing the recovery rate or making it difficult to produce foam.

[0035] The crosslinking agent is not particularly limited, but examples include triallyl isocyanurate, polyethylene glycol, zinc methacrylate, ethylene glycol dimethacrylate, and divinylbenzene.

[0036] The foamed resin composition in this invention may be foamed with a foaming agent.

[0037] While the foaming agent is not particularly limited, examples include organic chemical foams made from azo compounds such as azodicarbonamide and barium azodicarboxylate, nitroso compounds such as dinitrosopentamethylenetetramine and trinitrotrimethyltriamine, hydrazide compounds such as p,p'-oxybisbenzenesulfonyl hydrazide, and sulfonyl semicarbazide compounds such as p,p'-oxybisbenzenesulfonyl semicarbazide and toluenesulfonyl semicarbazide.

[0038] In addition, inorganic foaming agents such as baking soda can also be used.

[0039] The amount of foaming agent is preferably 3 to 20 parts by weight, and more preferably 6 to 18 parts by weight, per 100 parts by weight of the foaming resin composition.

[0040] This is because if the amount is less than 3 parts by weight, it may not foam sufficiently, and if it exceeds 20 parts by weight, it may not be possible to form a foam.

[0041] The foaming resin composition of the present invention may have foaming aids added to adjust the foaming rate.

[0042] Examples of foaming agents include zinc oxide, zinc stearate, and urea.

[0043] A filler may be added to the foamed resin composition in the present invention.

[0044] The fillers are not particularly limited, but examples include calcium carbonate, calcium oxide, diatomaceous earth, titanium dioxide, graphite, and starch.

[0045] The foaming resin composition of the present invention may optionally contain antioxidants, pigments, etc.

[0046] The present invention provides an example of a method for producing foam.

[0047] Bio-resin, crosslinking agent, crosslinking aid, and optionally foaming agent, foaming aid, filler, etc. are added and mixed using a heated mixing roll, pressurized kneader, extruder, etc., and the resulting compound is filled into a mold.

[0048] The mold filled with compound has a load capacity of 20 kgf / cm². 2 ~150 kgf / cm² 2 The mixture is sealed under pressure and heated at 120°C to 140°C for 60 to 80 minutes to produce an intermediate product.

[0049] The resulting intermediate product is foamed at 160°C to 165°C, and the resulting foam is compressed by sandwiching it between metal rolls to break the air bubbles (defoaming treatment), thereby forming vents and connecting holes.

[0050] Afterward, it can be manufactured by heating (restoration process) at 60°C to 80°C for 2 hours.

[0051] The foam in this invention is a foam having a thickness of 80% or more compared to the thickness of the intermediate foam.

[0052] Since it has a recovery rate of 80% or more, it can be suitably used as a sealing material for air conditioners and the like.

[0053] The restoration rate can be calculated as follows: "Thickness of foam after degassing and restoration (foam)" ÷ "Thickness of foam before degassing (intermediate foam)" × 100. [Examples]

[0054] The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited thereto.

[0055] Table 1 shows the resins and additives used in the examples and comparative examples.

[0056] [Table 1]

[0057] As shown in Tables 2 to 4, each additive was added in the specified weight to 100 parts by weight of resin, then kneaded in a pressurized kneader, and the resulting compound was filled into a mold.

[0058] The compound used was 100 kgf / cm². 2 Under pressure, the mixture was heated for the temperatures (°C) and times (minutes) specified in Tables 2 to 4 to obtain the intermediate product.

[0059] After producing an intermediate foam by foaming the intermediate product at 165°C for 120 minutes, the intermediate foam was compressed using upper and lower metal rollers with different rotation speeds to break the air bubbles in the intermediate foam and form vents and communication holes.

[0060] The foam with interconnected holes was restored at 70°C for 2 hours to obtain the foams of the example and comparative example.

[0061] Each foam was evaluated as follows:

[0062] (exterior) We visually inspected the exterior and evaluated the products as follows: those without cracks or gas leaks were marked with "○", and those with cracks or gas leaks were marked with "×".

[0063] (Defoaming property) When the bubble membrane was ruptured, a "○" was given if all the bubbles in the foam were ruptured, a "×" was given if only a part of the foam was ruptured, or if the foam tore during rupture and could not be used as a product, and a "-" was given if the appearance was poor and defoaming could not be performed.

[0064] (Resilience) Each foam sample, with a thickness of 100 mm after degassing was completed, was degassed, heated at 70°C for 2 hours, and then its thickness was measured.

[0065] Foams with a thickness of 80 mm or more after heating were evaluated as "○", and foams with a thickness of less than 80 mm were evaluated as "×".

[0066] The results are shown in Tables 2 to 4. Each quantity is expressed in parts by weight. The "Temperature (°C) / Time (minutes)" in the tables are the values ​​used when preparing the intermediate product.

[0067] [Table 2]

[0068] [Table 3]

[0069] [Table 4]

[0070] Tables 2 to 4 demonstrate that the foam in this invention has many interconnected pores and is a highly resilient foam. [Industrial applicability]

[0071] The foam used in this invention is made from bio-resin, thus having a low environmental impact. Furthermore, because it contains many interconnected pores, it exhibits a high recovery rate between the thickness of the intermediate foam before defoaming and the thickness of the foam after defoaming and restoration treatment. Therefore, it is a foam that can be suitably used as a sealing material for air conditioners and the like. Therefore, this invention has high industrial applicability.

Claims

1. A foam obtained by foaming a foamable resin composition containing a bioresin made of biopolyethylene and / or bioethylene vinyl acetate copolymer, a crosslinking agent and a crosslinking aid, wherein the content of the crosslinking agent in the foamable resin composition is 0.60 parts by weight or more and 0.90 parts by weight or less per 100 parts by weight of the bioresin. A foam in which the crosslinking aid is contained in an amount of 0.05 parts by weight or more and 0.30 parts by weight or less per 100 parts by weight of the bio-resin.

2. The foam according to claim 1, wherein the crosslinking agent is dicumyl peroxide and the crosslinking aid is triallyl isocyanurate.

3. The foam according to claim 1 or 2, wherein the restoration rate of the thickness of the foam after defoaming and then restoring the intermediate foam is 80% or more relative to the thickness of the intermediate foam obtained by foaming the foamed resin composition.

4. The method for producing a foam according to claim 1 or 2, wherein the intermediate foam is a foam produced by heating the foamable resin composition at 120°C or higher and 140°C or lower for 60 minutes or more and 80 minutes, and then heating the intermediate product at 160°C or higher and 165°C or lower to produce foam, and the foam that has undergone the restoration treatment is a foam that has undergone a restoration treatment by heating at 60°C or higher and 80°C or lower for 2 hours after defoaming treatment.

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