JP2006316241A - Polyolefinic resin composition and method for producing polyolefinic resin foam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyolefinic resin composition suppressing formation of foreign materials, stably producible over a long period and having excellent productivity without requiring an aging step such as a heat treatment in production of a polyolefinic resin foam and to provide a method for producing the polyolefinic resin foam using the polyolefinic resin composition. <P>SOLUTION: The polyolefinic resin composition comprises 100 pts.wt. of a resin component consisting essentially of a polyolefinic resin, 0.01-2 pts.wt. of an organic peroxide, 0.005-1 pt.wt. of a radical scavenger and 0.05-20 pts.wt. of an acrylate or a methacrylate monomer. A reaction is carried out while melt kneading the polyolefinic resin composition to modify the resin component. A thermal degradation type chemical foaming agent is added to the modified resin component and the resultant foamable resin composition is heated to a temperature not lower than the degradation temperature of the foaming agent and foamed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a polyolefin resin composition and a method for producing a polyolefin resin foam using the same.

  Polyolefin resin foams such as polyethylene and polypropylene are excellent in lightness, heat insulation, flexibility, etc., and thus various studies have been made as suitable materials widely used for various heat insulating materials, cushioning materials, levitation materials, and the like. .

  For example, Patent Document 1 describes a method for producing a polyolefin resin foamable composite sheet using a polyolefin resin, an oxime compound, an acrylic compound, and the like. A polyolefin resin, a dioxime compound, a bismaleimide compound, allyl A modification monomer selected from the group consisting of a polyfunctional monomer, a (meth) acrylic polyfunctional monomer, a quinone compound, and a combination of two or more of these, and modifying the resin, The resulting modified resin is kneaded with a pyrolytic chemical foaming agent, the resulting foamable resin composition is shaped into a sheet, and the resulting foamable resin sheet is heated on at least one side. Polyolefin-based resin foaming property, characterized by laminating sheet-like materials having strength capable of suppressing foaming in the in-plane direction when foaming Discloses such method of manufacturing a case sheet, the obtained modified resin are also disclosed process for producing a polyolefin resin foam composite sheet to blend this same type or unmodified polyolefin resin heterologous. By these methods, a polyolefin resin foamable composite sheet having both foamability and moldability can be produced.

  On the other hand, Patent Document 2 discloses a step of obtaining a partially crosslinked polypropylene resin by melting and mixing a composition containing a polypropylene resin, an organic peroxide, and an oxime compound, and a polypropylene resin containing the partially crosslinked polypropylene resin. A polypropylene-based resin foam comprising a step of supplying a mixed composition and a volatile foam to an extruder to obtain a uniform molten mixture, and a step of foaming the molten mixture while being extruded from the extruder into a low-pressure zone A manufacturing method is disclosed. In this method, a polypropylene resin foam excellent in closed cell properties can be produced.

  Further, Patent Document 3 discloses that in a method of modifying a crystalline polypropylene with an organic peroxide and a crosslinking aid to obtain a modified polypropylene, diacrylate and / or triacrylate as an organic peroxide and the crosslinking aid. The melt tension (MS) and the intrinsic viscosity [η] satisfy a specific relationship, and the boiling xylene extraction residual ratio is within a specific range, characterized in that A method for producing a modified polypropylene is disclosed. In this method, a polypropylene resin composition excellent in melt tension can be obtained.

  Further, in Patent Document 4, a composition containing a polypropylene resin, an oxime compound and a polyfunctional acrylic monomer is melt-mixed to obtain a partially crosslinked polypropylene resin, and a thermally decomposed chemical foam is formed on the modified resin component. A method for producing a polyolefin resin foam characterized by adding an agent and heating the resulting foamable resin composition to a temperature equal to or higher than the decomposition temperature of the foaming agent is disclosed. Also in this method, a polypropylene resin foam excellent in melt tension and closed cell properties can be produced.

Japanese Patent No. 3117678 Japanese Examined Patent Publication No. 4-64536 JP-A-7-304815 JP 2004-9470 A

  However, according to the study of the present inventor, in the method of Patent Document 1, when a quinonedioxime compound is used as a modification monomer, good foamability is obtained due to its high reactivity, When a large amount of phenylenediamine is produced, the mold is likely to be clogged during shaping, or blackening due to adhesion to the roll is likely to occur, and it is difficult to stably produce for a long time. there were. In addition, when an acrylic polyfunctional monomer is used as the modifying monomer, the modification ability of the polyolefin resin is likely to be insufficient, and the melt tension of the resin to ensure foamability is less likely to be exhibited. There is a problem that it is difficult to produce a foam having a magnification, and in order to ensure sufficient foamability, a curing process with hot water or the like may be required for the obtained sheet. In some cases, the productivity is remarkably lowered, for example, it is necessary to perform heating for about 5 to 20 minutes in the vicinity of ° C.

  In relation to the above, Patent Document 2 discloses that a quinone dioxime compound is used as an oxime compound, a melt elastic modulus of a polypropylene resin is improved, and 1,1,2,2-tetrafluorodichloroethane is used as a volatile foaming agent. Although it is described that the foamability is improved and a good closed cell ratio is obtained, according to the study of the present inventor, since a large amount of phenylenediamine that causes foreign matters is generated as described above, There was a problem that it was difficult to produce stably.

  Patent Document 3 describes that a modified polypropylene excellent in melt tension is obtained by heat treatment at a temperature of 180 to 300 ° C. using an acrylic monomer as a modification aid. As long as a process is required, there is a problem that productivity is remarkably lowered as described above.

  Patent Document 4 describes that a modified polypropylene having excellent melt tension and good closed cell ratio can be obtained by using a quinonedioxime compound as the oxime compound and a polyfunctional acrylic monomer as the second monomer. Although improved over Patent Document 1 or 2, it cannot always be said that a sufficient effect is obtained, and there is a problem that productivity is remarkably lowered because foreign matters are generated. In addition, since the modification temperature and the kneading temperature of the foaming agent are different, the kneading process of the foaming agent must be carried out in a separate process, requiring two extruders, and there is a problem that capital investment is expensive.

  The object of the present invention is to solve the above-mentioned problems, and in the production of polyolefin resin foams, the generation of foreign substances is suppressed and production can be performed stably for a long time, and a curing process such as heat treatment is not required. An object of the present invention is to provide a polyolefin resin composition excellent in productivity and a method for producing a polyolefin resin foam using the same, which can simultaneously carry out the kneading process of the agent.

  The polyolefin resin composition according to claim 1, wherein 0.01 to 2 parts by weight of an organic peroxide and 0.005 to 1 part by weight of a radical scavenger with respect to 100 parts by weight of a resin component mainly composed of a polyolefin resin. And 0.05 to 20 parts by weight of a (meth) acrylate monomer.

  The polyolefin resin composition according to claim 2 is obtained by adding 0.05 to 10 parts by weight of an antioxidant to the resin composition according to claim 1.

  In the polyolefin resin composition according to claim 3, the antioxidant added to the polyolefin resin composition according to claim 2 is a combination of a phenolic antioxidant and a phosphorus antioxidant. It is characterized by being.

  The method for producing a polyolefin resin foam according to claim 4 is a modified resin in which the polyolefin resin composition according to any one of claims 1 to 3 is reacted while melt kneaded to modify a resin component. A thermal decomposable chemical foaming agent is added to the components, and the resulting foamable resin composition is heated to a temperature equal to or higher than the decomposition temperature of the foaming agent to cause foaming.

  The method for producing a polyolefin resin foam according to claim 5 is the method for producing a polyolefin resin foam according to claim 4, wherein the modification temperature is set to 170 to 200 ° C., and azodicarbonamide is used as a pyrolytic chemical foaming agent. It is characterized by adding a foaming agent and foaming in one extruder.

  The polyolefin resin composition of the present invention comprises 0.01 to 2 parts by weight of an organic peroxide, 0.005 to 1 part by weight of a radical scavenger, and 100 parts by weight of a resin component mainly composed of a polyolefin resin. , (Meth) acrylate monomer 0.05 to 20 parts by weight, in the production of polyolefin resin foam, generation of foreign matter is suppressed and stable production for a long time, heat treatment, etc. No curing process is required and the productivity is excellent.

  In addition, a composition containing an antioxidant in a resin composition is a resin composition suitable for foaming, in which the resin is modified without causing crosslinking inhibition during reaction molding and without reducing crosslinking after crosslinking. It can be a thing. In particular, a composition containing an antioxidant in which a phenolic antioxidant and a phosphorus antioxidant are used in combination does not cause crosslinking inhibition during reaction molding even when added together with a crosslinking agent, and crosslinking after crosslinking. The resin can be modified without lowering the resin composition, and a resin composition in which foaming performance does not deteriorate can be obtained.

  Furthermore, in the method for producing a polyolefin resin foam of the present invention, the polyolefin resin composition is reacted while melt-kneaded to modify the resin component, and a pyrolytic chemical foaming agent is added to the modified resin component. The foamable resin composition obtained is characterized in that it is heated to a temperature equal to or higher than the decomposition temperature of the foaming agent and foamed. It is possible to provide a method for producing a polyolefin resin foam excellent in productivity without requiring a curing step such as heat treatment.

  Furthermore, in the method for producing a polyolefin resin foam of the present invention, the polyolefin resin composition is reacted while melt kneaded to modify the resin component, and the modified resin component is thermally decomposed at the time of melt kneading. Add a type chemical foaming agent, or add a pyrolytic foaming agent from the side feeder during the modification process, and heat the foamable resin composition obtained above the foaming agent decomposition temperature to foam. Since it is characterized, a curing step such as heat treatment is unnecessary, the foaming agent kneading process can be carried out with a single molding machine, the productivity is excellent, and the polyolefin resin foam can be provided with simple equipment.

Hereinafter, the present invention will be described in detail.
The polyolefin resin as the main component of the resin component in the present invention is not particularly limited as long as it is a homopolymer of an olefin monomer or a copolymer containing the same as a main component. Polyethylene such as high-density polyethylene and linear low-density polyethylene, propylene homopolymer, propylene random polymer, propylene block polymer and other polypropylene, polybutene, ethylene-propylene copolymer, ethylene-propylene-diene terpolymer, Examples of the copolymer include ethylene-butene copolymer, ethylene-vinyl acetate copolymer, ethylene-acrylic acid ester copolymer and other ethylene-based copolymers. Among them, polyethylene and polypropylene are preferably used. These polyolefin resin may be used independently and 2 or more types may be used together.

  In the present invention, the resin component refers to a resin composition in which the proportion of the polyolefin resin is 70 to 100% by weight. Resins other than the polyolefin resin constituting the resin component are not limited, and examples thereof include polystyrene and styrene elastomer. If the proportion of the polyolefin resin in the resin component is less than 70% by weight, not only the light weight, chemical resistance, flexibility, elasticity, etc. that are characteristic of the polyolefin resin can be exhibited, but also the melt viscosity necessary for foaming is secured. This is not preferable because it may be difficult. Resins other than the polyolefin-based resin may be used alone or in combination of two or more.

  Examples of the organic peroxide in the present invention include 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexyne- 3, t-butylperoxybenzene, benzoyl peroxide, α, α′-bis (t-butylperoxy) diisopropylbenzene, di-tbutyl peroxide, dicumyl peroxide and the like. These may be used alone or in combination of two or more.

  The radical scavenger used in the present invention is a compound capable of reacting with an alkyl radical species and capable of binding to a (meth) acrylate monomer after binding with the alkyl radical. Examples of the compound having such an action include quinones such as p-benzoquinone, p-naphthoquinone, 2-t-butyl p-benzoquinone and 2,5-diphenyl p-benzoquinone, 1,4 naphthoquinone, 2-hydroxy- Examples thereof include naphthoquinones such as 1,4-naphthoquinone and vitamin K, phenothiazines such as phenothiazine, bis- (α-methylbenzyl) phenothiazine, 3,7-dioctylphenothiazine, and bis- (α-dimethylbenzyl) phenothiazine. The above compounds may be used in combination of two or more.

The (meth) acrylate monomer used in the present invention means a compound having two or more (meth) acryloyloxy groups [sometimes referred to as (meth) acrylic groups] in the molecule. For example, (meth) acryloyl As compounds having two oxy groups, alkanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neo Pentyl glycol di (meth) acrylate, dimethylol tricyclodecane di (meth) acrylate, ethylene glycol adduct di (meth) acrylate of bisphenol A, propylene glycol adduct di (meth) of bisphenol A Examples of the compound having three acryloyloxy groups include trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, trimethylolpropane ethylene oxide-added tri (meth) acrylate, and glycerin propylene oxide-added tri (Meth) acrylate, tri (meth) acryloyloxyethyl phosphate, and the like. Examples of the compound having four (meth) acryloyloxy groups include pentaerythritol tetra (meth) acrylate and ditrimethylolpropane tetra (meth) acrylate. Can be mentioned. The said (meth) acrylate monomer may be used independently and 2 or more types may be used together.
The above “(meth) acryloyloxy group” means “acryloyloxy group” or “methacryloyloxy group”, and “(meth) acrylic group” means “acrylic group” or “methacrylic group”. To do.

  As a composition of the polyolefin resin composition of this invention, an organic peroxide is 0.01-2 weight part with respect to 100 weight part of said resin components, The said (meth) acrylate monomer is 0.05-20. The parts by weight and the radical scavenger are 0.005 to 1 parts by weight.

  In the above, when the organic peroxide is less than 0.01 part by weight, the reactivity when modifying the polyolefin resin becomes insufficient, and it becomes difficult to obtain a good foam. In addition, when it exceeds 2 parts by weight, decomposition is prioritized in the case of polypropylene resin, and in the case of polyethylene resin, shaping by extrusion or the like becomes difficult due to progress of gelation, and a good foam is obtained. Becomes difficult.

  Further, when the (meth) acrylate monomer is less than 0.05 parts by weight or exceeds 20 parts by weight, the reactivity when modifying the polyolefin resin in any case (hereinafter also referred to as “modification effect”) Becomes insufficient, and it becomes difficult to obtain a good foam.

  Further, when the radical scavenger is less than 0.005 parts by weight or more than 1 part by weight, in any case, the modification effect of the polyolefin-based resin becomes insufficient and it is difficult to obtain a good foam. Become.

In the polyolefin-based resin composition of the present invention, by adding an antioxidant to the resin composition and molding, the resin does not cause cross-linking inhibition during reaction molding and does not reduce cross-linking after cross-linking. Can be modified.
The antioxidant that can be used in the present invention is not particularly limited, and any of a phenolic antioxidant, a phosphorus antioxidant, and a sulfur antioxidant can be used. It is preferable to use a hydroperoxide decomposing agent such as a phosphorus antioxidant or a sulfur-based antioxidant together. In particular, the combined use of a phenolic antioxidant and a phosphorus antioxidant is foamed even if added together with a crosslinking agent. This is preferable because the performance does not deteriorate.

  Examples of the phenolic antioxidant include 2,6-di-tert-butyl-4-methylphenol, n-octadecyl-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 2 -Tert-butyl-6- (3-tert-butyl-2-hydroxy-5-methylbenzyl) -4-methylphenyl acrylate, tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxy Phenyl) propionate] methane and the like. These phenolic antioxidants may be used alone or in combination of two or more.

  Examples of the sulfur-based antioxidant include dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3′-thiodipropionate, penta An erythrityl tetrakis (3-lauryl thiopropionate) etc. are mentioned. These organic sulfur-based antioxidants may be used alone or in combination of two or more.

  Further, examples of the phosphorus-based antioxidant include tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-dicumylphenyl) pentaerythritol-diphosphite, and bis (2,6-diphenyl). -T-butyl-4-methylphenyl) pentaerythritol-diphosphite, tetrakis (2,4-t-butylphenyl) [1,1-biphenyl] -4,4'-diylbisphosphonite, bis [2,4 -Bis (1,1-dimethylethyl) -6-methylphenyl] ethyl ester phosphorous acid, di-t-butyl-m-cresyl-phosphonite, bis (2,4-di-t-butylphenyl) pentaerythritol di- A phosphite etc. are mentioned. These phosphorus antioxidants may be used alone or in combination of two or more.

  As for the compounding quantity of antioxidant, 0.05-10 weight part is preferable with respect to 100 weight part of resin components. When the amount of the antioxidant is less than 0.05 parts by weight, deterioration after molding occurs, and when it exceeds 10 parts by weight, the extrudability is unstable.

  The method for producing a polyolefin resin foam using the polyolefin resin composition of the present invention is not particularly limited. For example, the resin component is modified by reacting while melting and kneading the polyolefin resin composition, A method in which a thermally decomposable chemical foaming agent is added to the modified resin component and the resulting foamable resin composition is heated to a temperature equal to or higher than the decomposition temperature of the foaming agent or foamed, or volatilized in the modified resin component. Examples thereof include a method in which a foaming agent composition is added and foamed while shaping the obtained foamable resin composition.

  Among these, the former method using a pyrolytic chemical foaming agent is preferable in that it is easy to control foaming properties depending on heating conditions.

The volatile foaming agent is not particularly limited, and examples thereof include hydrocarbons such as propane, butane, pentane, and hexane, methyl chloride, ethylene chloride trichlorofluoromethane, dichlorofluoromethane, difluorochloromethane, 1,1,2 , 2-tetrafluorodichloroethane, 1,1,2-trifluorotrichloroethane and other halogenated carbons, and CO ₂ and N ₂ inert gases.

  The pyrolytic chemical foaming agent is not particularly limited. For example, azodicarbonamide (ADCA), benzenesulfonyl hydrazide, dinitrosopentamethylenetetramine, toluenesulfonyl hydrazide, 4,4-oxybis (benzenesulfonylhydrazide) Among them, ADCA is more preferably used. These pyrolytic chemical foaming agents may be used alone or in combination of two or more.

As a modification method of the resin component, for example, the resin component, an organic peroxide, a radical scavenger, and a (meth) acrylate monomer are charged into a kneading apparatus such as a screw extruder or a kneader and melt-kneaded. Is taken. The melt kneading temperature is 170 ° C. or higher and below the decomposition temperature of the polyolefin resin, and is preferably 180 ° C. to 240 ° C. When the melt kneading temperature is less than 170 ° C., the resulting resin is likely to be insufficiently modified, and the polyolefin resin exceeding 250 ° C. is likely to be decomposed.
More preferably, the temperature is 180 ° C. to 190 ° C. because a foaming agent can be added simultaneously. When the melt kneading temperature is less than 170 ° C., the resulting resin tends to be insufficiently modified, and when it exceeds 190 ° C., the decomposition of ADCA begins.

  When using a thermally decomposable chemical foaming agent, the foamable resin composition may be produced, for example, by adding a thermally decomposable chemical foaming agent to the modified resin component, at a temperature at which the foaming agent does not decompose, and the resin. Examples thereof include a method for producing a foamable resin composition by kneading within a melting temperature range. Furthermore, it is preferable to add a pyrolyzable foaming agent at the same time when the modified resin is produced, or to add a pyrolyzable foaming agent from a side feeder provided in the molding machine during resin modification because the process becomes easy.

  The obtained foamable resin composition is kneaded with an apparatus such as a screw extruder or a kneader, and then shaped into a predetermined shape with a mold, a press or the like and heated and foamed. The temperature during the kneading and shaping is preferably 150 to 200 ° C, more preferably 160 to 185 ° C. The temperature at the time of foaming is usually within a temperature range from a temperature higher than the decomposition temperature of the thermal decomposition type chemical blowing agent to a temperature lower than the thermal decomposition temperature of the polyolefin resin.

  For example, a method of foaming a sheet-shaped shaped article (hereinafter also referred to as “foamable sheet”) obtained by shaping the foamable resin composition above the decomposition temperature of the foaming agent, For example, it is preferably performed using a continuous foaming apparatus. The foaming method using the continuous foaming apparatus is not particularly limited. For example, a take-up foaming machine that continuously foams the foamable sheet while taking the sheet at the outlet side of the heating furnace, A method of foaming using a belt-type foaming machine, a vertical foaming furnace, a horizontal foaming furnace, a hot air thermostat, or a method of foaming in a hot bath such as an oil bath, a metal bath, a salt bath, etc. Can be mentioned.

  In the case of foaming using a volatile foaming agent, for example, in the method for modifying a resin component described above, the resin component, the organic peroxide, the radical scavenger, and the (meth) acrylate monomer are melt-kneaded using a screw extruder. In such a state, a method of injecting the volatile foaming agent under pressure from a pressure inlet provided in the middle of the extruder and foaming while extruding under low pressure is preferable.

The present invention will be specifically described below by showing examples and comparative examples.
In addition, this invention is not limited only to the following Example.

Example 1
(1) Preparation and modification of polyolefin resin composition As a screw extruder for reaction, BT40 (manufactured by Plastic Engineering Laboratory Co., Ltd.), a co-rotating twin screw extruder was used. This is equipped with a self-wiping double thread, L / D is 35 and D is 39 mm. The cylinder barrel is composed of first to fourth barrels from the upstream side to the downstream side of the extruder, the die is a three-hole strand die, and a vacuum vent is installed in the fourth barrel to collect volatile components.

The operating conditions are as follows.
-Screw rotation speed: 60rpm
・ Cylinder barrel set temperature: 1st barrel; 180 ℃
2nd barrel; 200 ° C
3rd barrel; 200 ° C
4th barrel; 200 ° C
Dai; 200 ℃

  First, polyolefin resin and radical scavenger are separately supplied from the rear end hopper to the reaction screw extruder having the above structure by a screw feeder, and organic peroxide and (meth) acrylate monomer are respectively metered into the extruder. The polyolefin-based resin composition comprising the above-mentioned polyolefin-based resin, an organic peroxide, a radical scavenger, and a (meth) acrylate monomer is reacted while being melted and mixed in the extruder to modify the polyolefin-based resin. Thus, a resin component modified in the extruder (hereinafter also referred to as “modified resin composition”) was obtained. At this time, the volatile matter generated in the extruder was evacuated by a vacuum vent.

The polyolefin resin was a polypropylene random copolymer (“EG8” manufactured by Mitsubishi Chemical Corporation, MI: 0.8 g / 10 min, density: 0.9 g / cm ³ ), and the supply amount was 10 kg / h.

  The organic peroxide was perhexine 25B (manufactured by NOF Corporation), and the supply amount was 0.1 parts by weight with respect to 100 parts by weight of the polyolefin resin.

  The radical scavenger was p-benzoquinone (manufactured by Wako Pure Chemical Industries, Ltd.), and the supply amount was 0.05 parts by weight with respect to 100 parts by weight of the polyolefin resin.

  The (meth) acrylate monomer was trimethylolpropane triacrylate (trifunctional acrylic monomer TMPTA, manufactured by Kyowa Kasei Co., Ltd.), and the supply amount was 1 part by weight with respect to 100 parts by weight of the polyolefin resin.

  The modified resin composition obtained in the extruder as described above was discharged from a strand die attached to the extruder, cooled with water, and cut with a pelletizer to obtain pellets of the modified resin composition.

(2) Preparation of expandable resin sheet The screw extruder for foaming agent kneading is a TEX-44 type (manufactured by Nippon Steel), a co-rotating twin screw extruder, which is equipped with a self-wiping twin screw, Its L / D is 45.5 and D is 47 mm. The cylinder barrel is composed of 1st to 12th barrels from the upstream side to the downstream side of the extruder, and the forming die is a 7-hole strand die.

The temperature setting categories are as follows.
1st barrel is always cooled 1st zone; 2nd to 4th barrel 2nd zone; 5th to 8th barrel 3rd zone; 9th to 12th barrel 4th zone; Die and adapter part

  A side feeder is installed in the sixth barrel for supplying the foaming agent, and a vacuum vent is installed in the eleventh barrel for recovering volatile components.

The operating conditions are as follows.
-Screw rotation speed: 40rpm
・ Cylinder barrel set temperature: 1st zone; 150 ℃
Second zone: 170 ° C
Third zone: 180 ° C
Zone 4; 160 ° C

Weight of pellets of modified resin composition obtained as described above and unmodified polypropylene random copolymer (“MA3” manufactured by Mitsubishi Chemical, MI; 11 g / 10 min, density: 0.9 g / cm ³ ) The mixture was dry blended at a ratio of 1: 1 and supplied to a foam extruder kneading screw extruder. The amount of pellets supplied was 20 kg / hr. Moreover, the foaming agent was supplied to the same extruder from the side feeder and dispersed. The blowing agent was azodicarbonamide (ADCA: VINYHALL AC-K3 manufactured by Eiwa Chemical Industry Co., Ltd.), and the supply amount was 1.2 kg / hr.

  The foamable resin composition obtained in the extruder by kneading the modified resin component and the foaming agent is discharged from a T die attached to the extruder, shaped into a sheet using a cooling roll, and the width A foamable resin sheet having a thickness of 1000 mm and a thickness of 0.6 mm was obtained.

(3) Preparation of resin foam A square sample with a side of 100 mm was cut out from the obtained foamable resin sheet, and foamed on a stainless steel bat on which foam talc was laid in a hot air oven at 220 ° C., to obtain a polypropylene resin. A foam was obtained.

(4) Performance evaluation In the above, the following performance evaluation was performed. The results are shown in Table 1.
(I) Extrusion operability In order to evaluate whether or not stable production is possible for a long time, in the adjustment of the foamable resin sheet, the time from the start of extrusion to the break of the sheet due to the generation of foreign matters was measured.
(Ii) Foaming property With respect to the resin foam obtained as described above, the expansion ratio was measured according to JIS K6767.

(Example 2)
In obtaining the modified resin composition, a resin foam was produced in the same manner as in Example 1 except that the radical scavenger was 2-hydroxynaphthoquinone (manufactured by Kawasaki Kasei Kogyo Co., Ltd.) and the supply amount was 0.06 parts by weight. The extrusion operability and foamability were evaluated. The results are shown in Table 1.

(Example 3)
In obtaining the modified resin composition, a resin foam was produced in the same manner as in Example 1 except that phenothiazine (manufactured by Wako Pure Chemical Industries, Ltd.) was used as the radical scavenger, and extrusion operability and foamability were evaluated. The results are shown in Table 1.

Example 4
In obtaining the modified resin composition, a resin foam was prepared in the same manner as in Example 1 except that the organic peroxide was Perbutyl Z (manufactured by NOF Corporation) and the barrel temperature was as follows. And foamability was evaluated. The results are shown in Table 1.
・ Cylinder barrel set temperature: 1st barrel; 180 ℃
Second barrel: 180 ° C
3rd barrel; 180 ° C
4th barrel; 180 ° C
Die: 180 ℃

(Example 5)
In obtaining the modified resin composition, a resin foam was prepared in the same manner as in Example 1 except that the supply amount of the radical scavenger was 0.1 parts by weight and the supply amount of (meth) acrylate was 2 parts by weight. The extrusion operability and foamability were evaluated. The results are shown in Table 1.

(Example 6)
In obtaining the modified resin composition, the same procedure as in Example 1 was performed except that the (meth) acrylate monomer was trimethylolpropane trimethacrylate (trifunctional acrylic monomer TMPTMA, manufactured by Kyowa Kasei Co., Ltd.) and the supply amount was 2 parts by weight. Resin foams were prepared, and extrusion operability and foamability were evaluated. The results are shown in Table 1.

(Comparative Example 1)
In obtaining the modified resin composition, the organic oxide and (meth) acrylate monomer were not used, the supply amount of P-quinonedioxime as the quinonedioxime compound was 0.8 parts by weight, and the barrel temperature was as follows. Except that, a resin foam was produced in the same manner as in Example 1, and the extrusion operability and foamability were evaluated. The results are shown in Table 1.
・ Cylinder barrel set temperature: 1st barrel; 180 ℃
2nd barrel; 220 ° C
3rd barrel; 220 ° C
4th barrel; 220 ° C
Die: 220 ° C

(Comparative Example 2)
In obtaining a modified resin composition, a comparative example except that the supply amount of trimethylolpropane trimethacrylate as a (meth) acrylate monomer was 0.6 parts by weight and the supply amount of P-quinonedioxime was 0.4 parts by weight. Resin foams were prepared in the same manner as in No. 1, and extrusion operability and foamability were evaluated. The results are shown in Table 1.

(Comparative Example 3)
In obtaining the modified resin composition, a resin foam was prepared in the same manner as in Example 1 except that the radical scavenger was not added and the amount of organicated oxide supplied was 0.01 parts by weight. And foamability were evaluated. The results are shown in Table 1.

(Comparative Example 4)
In obtaining the modified resin composition, a resin foam was prepared in the same manner as in Example 1 except that the radical scavenger was not added and the amount of organic oxide supplied was 0.5 parts by weight. And foamability were evaluated. The evaluation results are shown in Table 1.

(Example 7)
As a reaction screw extruder, BT40 (Plastics Engineering Laboratory Co., Ltd.) co-rotating twin screw extruder was used. This is equipped with a self-wiping double thread, L / D is 35 and D is 39 mm.

The operating conditions are as follows.
-Screw rotation speed: 50rpm
・ Cylinder barrel set temperature: 1st barrel; 180 ℃
2nd barrel; 200 ° C
3rd barrel; 200 ° C
4th barrel; 180 ° C
Die: 150 ° C

  First, polyolefin resin and radical scavenger are separately fed from the rear end hopper to the reaction screw extruder having the above structure by a screw feeder, and each (meth) acrylate monomer and organic peroxide are metered into the extruder. The polyolefin resin is modified by melting and mixing in the extruder with a polyolefin resin composition comprising the polyolefin resin, an organic peroxide, a radical scavenger, and a (meth) acrylate monomer. The modified resin composition was obtained in the extruder, and the volatile foaming agent was injected from the press-fitting hole provided in the middle of the extruder, and the modified resin composition and the foaming agent were further kneaded to obtain the modified resin composition in the extruder. The foamable resin composition is discharged from a one-hole nozzle-like die (φ5 mm, length 50 mm) attached to the same extruder. It is foamed by pressure release after the discharging, to obtain a polyolefin resin foam.

The polyolefin resin is a polypropylene random copolymer (“EG8” manufactured by Mitsubishi Chemical Corporation, MI: 0.8 g / 10 min, density: 0.9 g / cm ³ , melting point 143 ° C.), and its supply amount is 10 kg / hr. It was.

  The organic peroxide was perhexine 25B (“Perhexine 25B” manufactured by NOF Corporation), and the supply amount was 0.1 parts by weight with respect to 100 parts by weight of the polyolefin resin.

  The radical scavenger was p-benzoquinone (manufactured by Wako Pure Chemical Industries, Ltd.), and the supply amount was 0.05 parts by weight with respect to 100 parts by weight of the polyolefin resin.

  The (meth) acrylate monomer was trimethylolpropane triacrylate (trifunctional acrylic monomer TMPTA, manufactured by Kyowa Kasei Co., Ltd.), and its supply amount was 1 part by weight with respect to 100 parts by weight of the polyolefin resin.

  The volatile foaming agent is 1,1,2,2-tetrafluorodichloroethane, and its supply amount is 20 parts by weight with respect to 100 parts by weight of the resin component mainly composed of polyolefin resin, and the supply pressure is 5.9 MPa. It was.

As a result of performing the following performance evaluation on the obtained resin foam, the expansion ratio was 23, the closed cell ratio was 80%, and the continuous extrusion time was 24 hours or more.
(Foaming)
About the resin foam obtained by the above, the expansion ratio was measured based on JISK6767.
(Closed cell rate)
It measured using the air comparison type hydrometer 1000 type | mold (made by Tokyo Science company).
(Continuous extrusion time)
In order to evaluate whether it can be stably produced for a long time, the time from the start of extrusion until the formation of a good foam due to the generation of foreign matter was measured.

(Comparative Example 5)
Instead of the quinonedioxime compound, the following mixture was used, and the supply amount thereof was 4 parts by weight with respect to 100 parts by weight of the resin component mainly composed of a polyolefin resin, and a (meth) acrylate monomer was used. A foam was produced in the same manner as in Example 7 except that it was not.
(Mixture composition)
Quinone dioxime: 0.8 part by weight Organic peroxide (DCP): 0.1 part by weight extender [Polyolefin resin (“EG8” manufactured by Mitsubishi Chemical Corporation) molded product): 3.1 parts by weight

  As a result of performing the same performance evaluation as in Example 3 on the obtained resin foam, the foaming ratio was 25 and the closed cell ratio was 80%, but the continuous extrusion time was 4 hours, and when it exceeded 4 hours, the black gel As a result, a good foam could not be produced.

(Example 8)
The melt tension (MS) of the pellet of the modified resin composition prepared in Example 1 was measured using a melt tension tester (“Capillary rheometer” manufactured by Toyo Seiki Seisakusho). The measurement conditions were a nozzle diameter of 2.095 mm, a measurement temperature of 230 ° C., a discharge speed from the nozzle of 20 mm / min, an air gap of 35 cm, and a take-off speed of 3.14 m / min. As a result, the melt tension was 3.9 g.

(Comparative Example 6)
The melt tension (MS) of the pellet of the modified resin composition (p-quinonedioxime 0.8 parts by weight) prepared in Comparative Example 1 was measured using a melt tension tester (“capillary rheometer” manufactured by Toyo Seiki Seisakusho). did. The measurement conditions were a nozzle diameter of 2.095 mm, a measurement temperature of 230 ° C., a discharge speed from the nozzle of 20 mm / min, an air gap of 35 cm, and a take-off speed of 3.14 m / min. As a result, the melt tension was 4.1 g.

(Comparative Example 7)
The melt tension of the modified resin composition pellets prepared in Comparative Example 3 was measured in the same manner as in Example 7. As a result, the melt tension of the modified resin was 2.2 g.

(Examples 9 to 11)
Polyolefin random copolymer (EG8) as an organic peroxide, perhexine 25B as a radical scavenger, 2-hydronaphthoxyquinone as a (meth) acrylate monomer, TMPTA as a polyolefin resin, phenol Tetrakis [methylene-3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate] methane (manufactured by Asahi Denka Co., Ltd .: AO60) as a system antioxidant, and distearing as a sulfur system antioxidant Table 2 In the same manner as in Example 1, the polyolefin resin composition and It was obtained Rekara polyolefin resin foam. The elongation viscosity and expansion ratio of the obtained foam were measured. The results are shown in Table 2.
In addition, adjustment and modification | denaturation of the polyolefin resin composition produced the strand using BT40 (made by a plastics engineering laboratory company) same direction rotation twin screw extruder. The die is a one-hole strand die, and the operating conditions are as follows.
-Screw rotation speed: 40rpm
・ Cylinder barrel set temperature: 1st barrel; 180 ℃
Second barrel: 180 ° C
3rd barrel; 180 ° C
4th barrel; 180 ° C
Die: 180 ℃
The extensional viscosity was measured at 180 ° C. with an extensional viscometer.

(Examples 12 to 16)
Polyolefin random copolymer (EG8) as an organic peroxide, perhexine 25B as a radical scavenger, 2-hydronaphthoxyquinone as a (meth) acrylate monomer, TMPTA as a polyolefin resin, phenol Example 11 using AO60 as a system antioxidant, NOCRACK 400 as a sulfur antioxidant, phosphorus antioxidant (Adeka 135A manufactured by Asahi Denka Co., Ltd.), and ADCA as a foaming agent in the proportions shown in Table 3. In the same manner as described above, a polyolefin resin composition and a polyolefin resin foam were obtained therefrom. The obtained resin composition was kneaded at 50 rpm using a plastograph (manufactured by Toyo Seiki) kneading desk type at 50 rpm, and then a predetermined amount of resin was taken out and pressure-pressed at 180 ° C., and 1 mm A viscoelasticity G ′ (0.1) / G ′ (10), which is a measure of the degree of crosslinking, was measured with a viscoelasticity evaluation apparatus (RDA2). The results are shown in Table 3.
The addition timing of the antioxidant was after crosslinking in Examples 12 and 13, and before crosslinking in Examples 14 and 16.
Here, viscoelasticity G ′ (0.1) / G ′ (10) was measured at 230 ° C. with a viscoelasticity evaluation apparatus RDA-2 manufactured by Rheometrics.

  As is clear from Tables 2 and 3, it can be seen that by adding an antioxidant, the extensional viscosity is improved compared to the comparative example, and there is an effect of capturing radicals that degrade and degrade the resin. It can be seen that the foaming performance does not deteriorate even when the combination of the agent and the phosphorus antioxidant is added together with the crosslinking agent. Further, by adding an antioxidant before or after crosslinking, the value of viscoelasticity G ′ (0.1) / G ′ (10) is improved, and radicals that degrade and degrade resin are removed. It turns out that there is an effect to capture.

(Example 17)
(1) Preparation and modification of polyolefin resin composition As a screw extruder for reaction, BT40 (manufactured by Plastic Engineering Laboratory Co., Ltd.), a co-rotating twin screw extruder was used. This is equipped with a self-wiping double thread, L / D is 35 and D is 39 mm. The cylinder barrel is composed of first to fourth barrels from the upstream side to the downstream side of the extruder, the die is a T die, the side feeder is supplied to the third barrel for supplying the blowing agent, and the fourth is used for recovering the volatile matter. A vacuum vent is installed in the barrel.

The operating conditions are as follows.
-Screw rotation speed: 50rpm
・ Cylinder barrel set temperature: 1st barrel; 175 ℃
Second barrel: 180 ° C
3rd barrel; 180 ° C
4th barrel; 180 ° C
Die: 180 ℃

  First, polyolefin resin and radical scavenger are separately supplied from the rear end hopper to the reaction screw extruder having the above structure by a screw feeder, and organic peroxide and (meth) acrylate monomer are respectively metered into the extruder. The polyolefin-based resin composition comprising the above-mentioned polyolefin-based resin, an organic peroxide, a radical scavenger, and a (meth) acrylate monomer is reacted while being melted and mixed in the extruder to modify the polyolefin-based resin. Then, the blowing agent was supplied from the side feeder installed in the third barrel. The foamable resin composition obtained in the extruder by kneading the modified resin component and the foaming agent is discharged from a T die attached to the extruder, shaped into a sheet using a cooling roll, and the width A foamable resin sheet having a thickness of 300 mm and a thickness of 0.6 mm was obtained.

The polyolefin resin was a polypropylene random copolymer (“EG7G” manufactured by Nippon Polypro Co., Ltd., MI: 1.3 g / 10 min, density: 0.9 g / cm ³ ), and the supply amount was 10 kg / h.

  The organic peroxide was perhexine 25B (manufactured by NOF Corporation), and the supply amount was 0.1 parts by weight with respect to 100 parts by weight of the polyolefin resin.

  The radical scavenger was 2-hydroxynaphthoquinone (manufactured by Kawasaki Kasei Kogyo Co., Ltd.), and the supply amount was 0.25 parts by weight with respect to 100 parts by weight of the polyolefin resin.

  The (meth) acrylate monomer was trimethylolpropane triacrylate (trifunctional acrylic monomer TMPTA, manufactured by Kyowa Kasei Co., Ltd.), and the supply amount was 1 part by weight with respect to 100 parts by weight of the polyolefin resin.

  The thermally decomposable foaming agent was azodicarbonamide (ADCA) (manufactured by Eiwa Kasei Kogyo Co., Ltd., VINYHALL AC-K3), and the supply amount was 0.6 kg / h.

(2) Preparation of resin foam A square sample with a side of 100 mm was cut out from the obtained foamable resin sheet, and foamed on a stainless steel bat on which foam talc was laid in a hot air oven at 220 ° C. to obtain a polypropylene resin. A foam was obtained.

(3) Performance evaluation In the above, the following performance evaluation was performed. The evaluation results are shown in Table 4.
(I) Foaming property With respect to the resin foam obtained as described above, the expansion ratio was measured according to JIS K6767.

(Example 18)
In obtaining a foamable resin sheet, a resin foam was prepared in the same manner as in Example 17 except that the (meth) acrylate monomer was trimethylolpropane trioligoacrylate (Biscoat 295D manufactured by Osaka Organic Chemical Industry Co., Ltd.). Sex was evaluated. The evaluation results are shown in Table 4.

(Example 19)
In obtaining a foamable resin sheet, a resin foam was produced in the same manner as in Example 17 except that the position of the side feeder was changed to the first barrel and the addition position of the foaming agent was changed, and the foamability was evaluated. . The evaluation results are shown in Table 4.

(Example 20)
In obtaining a foamable resin sheet, a resin foam was prepared in the same manner as in Example 17 except that a foaming agent was mixed with a radical scavenger and added all at once without using a side feeder, and foamability was evaluated. The evaluation results are shown in Table 4.

(Comparative Example 8)
(1) Preparation and modification of polyolefin resin composition As a screw extruder for reaction, BT40 (manufactured by Plastic Engineering Laboratory Co., Ltd.), a co-rotating twin screw extruder was used. This is equipped with a self-wiping double thread, L / D is 35 and D is 39 mm. As the forming die, a three-hole strand die was used.

The operating conditions are as follows.
・ Screw rotation speed: 200rpm
・ Cylinder barrel set temperature: 1st barrel; 180 ℃
2nd barrel; 220 ° C
3rd barrel; 220 ° C
4th barrel; 220 ° C
Die: 220 ° C

  First, a polyolefin resin and a quinonedioxime compound are separately supplied from the rear end hopper by a screw feeder to the reaction screw extruder configured as described above, and the polyolefin resin composition is reacted while being melted and mixed in the extruder. The polyolefin resin was modified to obtain a modified resin composition modified in the extruder. At this time, the volatile matter generated in the extruder was evacuated by a vacuum vent.

The polyolefin resin was a polypropylene random copolymer (“EG8” manufactured by Mitsubishi Chemical Corporation, MI; 0.8 g / 10 min, density: 0.9 g / cm ³ ), and the supply amount was 10 kg / h.

  The quinone dioxime compound is p-quinone dioxime (“Barunok GM-P” manufactured by Ouchi Shinsei Chemical Co., Ltd.), and its supply amount was 0.8 parts by weight with respect to 100 parts by weight of the polyolefin resin.

  The modified resin composition obtained in the extruder as described above was discharged from a strand die attached to the extruder, cooled with water, and cut with a pelletizer to obtain pellets of the modified resin composition.

(2) Preparation of foamable resin sheet The screw extruder for foaming agent kneading is a TEX-44 type (manufactured by Nippon Steel Works) co-rotating twin-screw extruder, which is equipped with a self-wiping twin screw, L / D is 45.5 and D is 47 mm. The cylinder barrel is composed of 1st to 12th barrels from the upstream side to the downstream side of the extruder, and the forming die is a 7-hole strand die.

The temperature setting categories are as follows.
1st barrel is always cooled 1st zone; 2nd to 4th barrel 2nd zone; 5th to 8th barrel 3rd zone; 9th to 12th barrel 4th zone; Die and adapter part

  A side feeder is installed in the sixth barrel for supplying the foaming agent, and a vacuum vent is installed in the eleventh barrel for recovering volatile components.

The operating conditions are as follows.
-Screw rotation speed: 40rpm
・ Cylinder barrel set temperature: 1st zone; 150 ℃
Second zone: 170 ° C
Third zone: 180 ° C
Zone 4; 160 ° C

The pellet of the modified resin composition obtained as described above and an unmodified polypropylene random copolymer (“MA3” manufactured by Nippon Polypro Co., Ltd., MI: 11 g / 10 min, density: 0.9 g / cm ³ ) Dry blending was performed at a weight ratio of 1: 1, and the mixture was supplied to a foam extruder kneading screw extruder. The pellet supply rate was 20 kg / h. Moreover, the foaming agent was supplied to the same extruder from the side feeder and dispersed. The blowing agent was azodicarbonamide (ADCA), and the supply amount was 1.2 kg / h.

  The foamable resin composition obtained in the extruder by kneading the modified resin component and the foaming agent is discharged from a T die attached to the extruder, shaped into a sheet using a cooling roll, and the width A foamable resin sheet having a thickness of 300 mm and a thickness of 0.6 mm was obtained.

(3) Preparation of resin foam A square sample with a side of 100 mm was cut out from the obtained foamable resin sheet, and foamed on a stainless steel bat on which foam talc was laid in a hot air oven at 220 ° C., to obtain a polypropylene resin. A foam was obtained and evaluated for foamability. The evaluation results are shown in Table 4.

  As is apparent from Table 4, even when the chemical foaming agent is supplied using a single extruder, a high-magnification foam is obtained, and the continuous operability is improved.

  As described above, in the examples of the present invention, it has been found that the extrudability and foamability are excellent, and it has a high closed cell ratio, a long continuous extrusion time, and a high melt tension level. In the production of polyolefin resin foams, it has been found that the generation of foreign matters is suppressed and production can be performed stably for a long time.

  The polyolefin resin foam using the polyolefin resin composition of the present invention is excellent in extrusion operability and foamability, has a high closed cell ratio, a long continuous extrusion time, and a high melt tension. Therefore, the production of foreign matters is suppressed and production can be performed stably for a long time, and it is excellent in productivity that does not require a curing process such as heat treatment, and can be used effectively industrially.

Claims (5)

  0.01 to 2 parts by weight of organic peroxide, 0.005 to 1 part by weight of a radical scavenger, and 0.05 to (meth) acrylate monomer with respect to 100 parts by weight of a resin component mainly composed of a polyolefin resin. A polyolefin resin composition comprising 20 parts by weight.   A polyolefin-based resin composition comprising 0.05 to 10 parts by weight of an antioxidant added to the resin composition according to claim 1.   The polyolefin resin composition according to claim 2, wherein the antioxidant is a combination of a phenolic antioxidant and a phosphorus antioxidant.   A polyolefin resin composition according to any one of claims 1 to 3 is reacted while being melt-kneaded to modify a resin component, and a pyrolytic chemical foaming agent is added to the modified resin component. A method for producing a polyolefin-based resin foam, wherein the foamable resin composition is heated to a temperature equal to or higher than a decomposition temperature of the foaming agent and foamed.   The polyolefin resin foam according to claim 4, wherein the modification temperature is set to 170 to 200 ° C, azodicarbonamide is used as the thermal decomposition type chemical foaming agent, and foaming is performed by adding the foaming agent in one extruder. Body manufacturing method.