JP5270935B2 - Propylene resin composition for foam molded article and foam molded article thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a propylene-based resin composition for a foam molding which can be used for preferably producing a foam molding excellent in the balance of heat resistance, mechanical strength, flexibility and reversibility after deformation. <P>SOLUTION: The propylene-based resin composition for a foam molding comprises at least one selected from the group consisting of a propylene homopolymer and a propylene-&alpha;-olefin copolymer, wherein a peak melting temperature (Tm) measured by a differential scanning calorimeter (DSC) ranges from 140 to 165&deg;C; a melting energy calculated from the peak melting area at 140&deg;C or higher is less than 50 mJ/mg; and an amount of a solution composition at an elution temperature of 80&deg;C or higher is 50% by weight of a total solution composition amount on an elution curve given by temperature rising elution fractionation (TREF). <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a propylene-based resin composition suitable as a material for a foam molded article.

  Polyolefin foam molded products are excellent in weather resistance, chemical resistance, processability, hygiene, and recyclability, and are suitable for automobile interior materials, heat insulating materials, civil engineering / architectural joint materials, sound absorbing materials, sporting goods or food packaging. It is widely used for cushioning materials and heat insulation materials for air conditioning equipment. Among polyolefin foam moldings, polyethylene foam moldings are excellent in flexibility, extensibility, and the like, but have problems in heat resistance, mechanical strength, and the like. On the other hand, a polypropylene foam molded article having a higher melting point is superior in heat resistance and mechanical strength, which are problems of a polyethylene foam molded article, but lacks flexibility and is inferior in recoverability after deformation. There is.

In addition, foamed molded products other than polyolefin foamed molded products, such as polyurethane foamed molded products, have a problem in recyclability.
For these problems, an expandable resin composition containing a specific linear low density polyethylene (see, for example, Patent Document 1), an olefin resin composition containing a specific polypropylene resin and a specific polyethylene resin. Articles (see, for example, Patent Document 2), and crosslinked olefin resin foams (see, for example, Patent Document 3) having melting energy in a specific range have been proposed.

However, in any case, it has been difficult to obtain a foamed molded article having an excellent balance between heat resistance and mechanical strength, flexibility and recoverability after deformation.
JP 05-247247 A Japanese Patent Application Laid-Open No. 07-070350 JP 2000-248097 A

  It is an object of the present invention to provide a propylene-based resin composition for a foamed molded article that can suitably produce a foamed molded article having an excellent balance of heat resistance, mechanical strength, flexibility, and recoverability after deformation. To do.

As a result of intensive studies to solve the above problems, the present inventors have completed the present invention.
That is, the propylene-based resin composition for foam molded articles of the present invention is a propylene-based resin composition containing at least one selected from the group consisting of a propylene homopolymer and a propylene / α-olefin copolymer, The melting peak temperature (Tm) measured by a scanning calorimeter (DSC) is in the range of 140 to 165 ° C., and the melting energy of 140 ° C. or higher obtained from the melting peak area is less than 50 mJ / mg, and the temperature rise elution The elution curve obtained by fractionation (TREF) is characterized in that the amount of eluted components at an elution temperature of 80 ° C. or higher is 50% by weight or less of the total amount of eluted components.

  The propylene-based resin composition for foam molded articles of the present invention preferably has a melt flow rate (MFR; JIS K7210, 230 ° C., load 2.16 kg) in the range of 0.01 to 30 g / 10 minutes.

The α-olefin is preferably ethylene.
The foamed molded product of the present invention is obtained by foaming the above-mentioned propylene-based resin composition for foamed molded product.

  The propylene-based resin composition for foam molded articles of the present invention has a melting peak temperature (Tm) in the range of 140 to 165 ° C., which is higher than that of the polyethylene-based resin. For this reason, even in applications where conventional polyethylene foam moldings are problematic in terms of heat resistance or mechanical strength, foam moldings obtained by foaming the composition can be advantageously used.

  Furthermore, the propylene-based resin composition for foamed molded products of the present invention has a smaller melting energy and an elution component amount of 80 ° C. or higher in temperature rising elution fractionation compared to a normal propylene-based resin. For this reason, even in applications where conventional polypropylene foam moldings are problematic in terms of flexibility or recoverability after deformation, foam moldings obtained by foaming the composition can be advantageously used.

  That is, the foamed molded product obtained by foaming the propylene-based resin composition for foamed molded products of the present invention is excellent in the balance between heat resistance and mechanical strength, flexibility and recoverability after deformation. It was a polyolefin foam molding that was not present.

  Next, the propylene-based resin composition for foam molded article and the foam molded article of the present invention will be specifically described.

[Propylene resin composition for foamed molded article]
The propylene-based resin composition for foam molded articles of the present invention contains at least one selected from the group consisting of a propylene homopolymer and a propylene / α-olefin copolymer (hereinafter also referred to as “propylene-based resin”). Propylene-based resin composition, obtained from (1) melting peak temperature (Tm) measured by a differential scanning calorimeter (DSC) and (2) melting peak area measured by a differential scanning calorimeter (DSC) In the elution curve obtained by melting energy of 140 ° C. or higher and (3) temperature rising elution fractionation (TREF), the elution component amount at an elution temperature of 80 ° C. or higher is in the range described below, and (4 ) The melt flow rate (MFR) is preferably in the range described below.

<Requirement (1): Melting peak temperature (Tm)>
The propylene-based resin composition for foam molded articles of the present invention has a melting peak temperature (Tm) measured by a differential scanning calorimeter (DSC) of 140 to 165 ° C., preferably 145 to 165 ° C., more preferably 150 to It is in the range of 165. When the melting peak temperature (Tm) is in the above range, the foamed molded product obtained by foaming the composition is excellent in heat resistance and mechanical strength.

<Requirement (2): Melting energy>
The propylene-based resin composition for foam molded articles of the present invention has a melting energy of 140 ° C. or higher obtained from the melting peak area measured by a differential scanning calorimeter (DSC), less than 50 mJ / mg, preferably 3 to 47 mJ / mg, more preferably in the range of 5-45 mJ / mg. When the melting energy is in the above range, the foamed molded product obtained by foaming the composition is excellent in flexibility and recoverability after deformation.

<Requirement (3): Temperature rising elution fractionation (TREF)>
In the elution curve obtained by temperature rising elution fractionation (TREF), the amount of elution component at an elution temperature of 80 ° C. or higher is preferably 50% by weight or less of the total elution component amount, It is in the range of 5 to 50% by weight, more preferably 10 to 50% by weight. When the elution component amount at an elution temperature of 80 ° C. or higher is in the above range, the foamed molded article obtained by foaming the composition is excellent in flexibility and recoverability after deformation.

  The above temperature rising elution fractionation is a known analytical method. In principle, the sample to be measured is completely dissolved in a solvent at a high temperature and then cooled to leave it in the solution. A thin polymer layer is formed on the surface of the active carrier. At this time, a polymer layer is formed in the order of a highly crystalline component that is easily crystallized, a low crystalline component that is difficult to crystallize, and an amorphous component. Next, when the temperature is raised continuously or stepwise, the amorphous component and the low crystalline component are eluted, and finally the high crystalline component is eluted, contrary to the above. In this way, the composition distribution of the polymer is analyzed from the amount of the eluted component at each temperature and the elution curve drawn by the elution temperature. For details of the measurement method, see, for example, Journal of Applied Polymer Science, Vol. 26, 4217-4231 (1981).

<Requirement (4): Melt flow rate (MFR)>
The propylene-based resin composition for foamed molded products of the present invention has a melt flow rate (MFR; JIS K7210, 230 ° C., load 2.16 kg) usually 0.01 to 30 g / 10 minutes, preferably 0.02 to 20 g. / 10 minutes, more preferably in the range of 0.03 to 10 g / 10 minutes. When the MFR is in the above range, the foamed molded product obtained by foaming the composition is excellent in the balance between moldability, mechanical strength, and appearance.

<Propylene homopolymer, propylene / α-olefin copolymer>
The propylene homopolymer used in the propylene-based resin composition for foam molded articles of the present invention is a highly stereopropylene homopolymer with high stereoregularity, low stereoregularity, amorphous or low crystalline A propylene homopolymer etc. are mentioned. These are used by appropriately mixing two or more kinds so as to satisfy the above requirements (1) to (3), or by appropriately mixing the propylene homopolymer and the propylene / α-olefin copolymer described later. Use. When a highly crystalline propylene homopolymer is used, the content of the highly crystalline propylene homopolymer in the propylene-based resin composition for foam molded articles is usually 50% by weight or less.

  The propylene / α-olefin copolymer used in the propylene-based resin composition for foam molded articles of the present invention is a random mixture of propylene and an α-olefin having 2 or more carbon atoms (excluding propylene, the same applies hereinafter). Or it is a block copolymer. These may be used alone or in combination of two or more.

  Examples of the α-olefin include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, 3-methyl-1-butene, 3-methyl-1-pentene, 4-methyl-1-pentene, 3-methyl-1-hexene, 3,3-dimethyl-1-butene, 3-ethyl-1-pentene, dimethyl-1-pentene, methylethyl -1-pentene, diethyl-1-hexene, trimethyl-1-pentene, dimethyl-1-hexene, 3,5,5-trimethyl-1-hexene, methylethyl-1-heptene, trimethyl-1-heptene, dimethyl- 1-octene, ethyl-1-octene, methyl-1-nonene, vinylcyclopentane, vinylcyclohexane, vinylnorbornane, etc. It is below. Among these, ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene and 1-octene are preferable, and ethylene is most preferable. These may be used alone or in combination of two or more.

The content of the structural unit derived from α-olefin in the propylene / α-olefin copolymer is usually more than 0 mol% and not more than 80 mol%, preferably 0.2 to 70 mol%.
More preferably, it exists in the range of 0.4-60 mol%. Among these, a copolymer having an α-olefin-derived constituent unit content of 10 mol% or less is a copolymer that satisfies the above requirement (1), and the α-olefin-derived constituent unit content is 10 mol. A copolymer exceeding% tends to be a copolymer that satisfies the requirements (2) and (3). Therefore, the propylene type | system | group which satisfies the said requirements (1)-(3) by using together 2 or more types of copolymers from which content of the structural unit derived from an alpha olefin differs, or mixing with the said propylene homopolymer. A resin composition can be obtained.

  The propylene homopolymer or propylene / α-olefin copolymer used in the present invention is a metallocene catalyst comprising a metallocene compound using a transition metal of Group IV of the periodic table and methylaluminoxane or alkylaluminum or alkylaluminum halide, vanadium. Propylene in the presence of a titanium catalyst, titanium trichloride or titanium tetrachloride supported on a magnesium compound such as magnesium chloride, anionic polymerization catalyst, radical polymerization catalyst, or propylene and α-olefin Can be obtained by copolymerization.

  The polymerization may be any method such as slurry polymerization, bulk polymerization, gas phase polymerization, and liquid phase polymerization. Such polymerization may employ any of batch, semi-batch, and continuous methods, and may employ either single-stage polymerization or multi-stage polymerization. In the multistage polymerization, the polymer may be produced by gas phase polymerization or liquid phase polymerization, or may be produced by combining gas phase polymerization and liquid phase polymerization. Further, during the polymerization, the molecular weight may be adjusted by introducing hydrogen, or the molecular weight of the obtained polymer may be adjusted by a molecular weight regulator (decomposing agent) such as an organic peroxide.

  In the propylene resin composition for foamed molded products of the present invention, at least one propylene resin selected from the group consisting of a propylene homopolymer and a propylene / α-olefin copolymer is usually 50% by weight or more. , Preferably 60% by weight or more.

<Additives>
The propylene-based resin composition for foamed molded products of the present invention includes, as necessary, an antioxidant, a processing stabilizer, a weathering stabilizer, a decomposition agent, a neutralizing agent, a crystal nucleating agent, a metal deactivator, and an ultraviolet absorber. You may add additives, such as an agent, a lubricant, a plasticizer, a flame retardant, an antistatic agent, and a coloring agent. What is necessary is just to determine suitably the addition amount of the said additive according to the various characteristics or molding conditions requested | required of the foaming molding obtained by foaming the propylene-type resin composition for foaming moldings of this invention.
Examples of the decomposing agent include peroxides such as perhexa 25B (manufactured by NOF Corporation).

[Method for producing propylene-based resin composition for foam molded article]
The propylene-based resin composition for foam molded articles of the present invention satisfying the above requirements (1) to (3), preferably the requirement (4), can be obtained by the following method.

  The melting peak temperature (Tm) and melting energy of the propylene resin depend on the stereoregularity and crystallinity of the resulting propylene resin. That is, when the stereoregularity of the propylene resin is high, its melting peak temperature (Tm) is usually 165 ° C. or higher, but at the same time, the melting energy is usually 100 mJ / mg or higher. On the other hand, when the stereoregularity of the propylene resin is lowered or the amount of α-olefin copolymerized with propylene is increased, the crystallinity is lowered and the melting energy is usually 1 mJ / mg or less.

In general, a propylene-based resin having a melting peak temperature (Tm) satisfying the above requirement (1) is obtained by homopolymerizing propylene or copolymerizing propylene and a small amount of α-olefin using the above known catalyst. Can be obtained. However, the melting energy of the propylene-based resin thus obtained is usually in the range of 60 to 100 mJ / mg.

  On the other hand, the amorphous or low crystalline propylene homopolymer or propylene / α-olefin copolymer usually does not have a melting peak temperature (Tm) or less than 140 ° C. Their melting energy is usually in the range of 0 to 30 mJ / mg.

  Therefore, a propylene homopolymer or a propylene / α-olefin copolymer (high crystalline component) having a melting peak temperature (Tm) in the range of 140 to 165 ° C., preferably 145 to 165 ° C., and a melting energy of 0 to By appropriately mixing an amorphous or low crystalline propylene homopolymer or propylene / α-olefin copolymer (low crystalline component) in the range of 30 mJ / mg, preferably 0 to 20 mJ / mg, A propylene-based resin composition that satisfies both the above requirements (1) and (2) can be obtained.

  The high crystalline component and the low crystalline component may be mixed by a so-called block copolymerization method in which the high crystalline component is first polymerized in a predetermined amount and then the low crystalline component is subsequently polymerized. Alternatively, a high crystallinity component and a low crystallinity component obtained in advance may be mixed or melt kneaded. Among these, it is preferable to produce a propylene resin composition by mixing two or more propylene resins obtained by a block copolymerization method.

  In addition, the elution component amount (requirement (3)) at the elution temperature of 80 ° C. or higher in the temperature rising elution fractionation (TREF) of the propylene resin composition is the stereoregularity of the propylene homopolymer or propylene / α-olefin copolymer. It decreases when the value is lowered, or decreases when the content of α-olefin in the propylene / α-olefin copolymer is increased. Here, the stereoregularity can be adjusted mainly by the selection of the polymerization catalyst.

  The MFR (requirement (4)) of the propylene-based resin composition can be adjusted by the polymerization conditions of the propylene-based resin, as well as the type and amount of the above decomposing agent added to the propylene-based resin, the decomposition temperature, and the decomposition time. It can also be adjusted appropriately by selecting.

[Manufacture of foam moldings]
The propylene-based resin composition for foam molded articles of the present invention can be mixed with a foaming agent and foam-molded by a conventionally known method. Examples of the foam molding method include normal pressure foaming, pressure foaming, extrusion foaming, injection foaming, press foaming, in-mold foaming, and bead foaming.

  Moreover, when foam-molding, the propylene-based resin composition may be subjected to a crosslinking treatment in order to impart appropriate viscoelasticity to the foam-molded product. In the case of crosslinking treatment, chemical crosslinking using a peroxide or electron beam crosslinking can be applied, and a polyfunctional monomer such as divinylbenzene can be used as a crosslinking aid if necessary.

  The foaming ratio of the foamed molded product obtained by foaming the propylene-based resin composition for foamed molded product of the present invention is usually 1.3 to 40 times, preferably 2 to 30 times.

<Foaming agent>
Examples of the foaming agent include physical foaming agents and chemical foaming agents. Each of the physical foaming agent or the chemical foaming agent may be used alone, or a physical foaming agent and a chemical foaming agent may be used in combination.

Examples of the physical foaming agent include nitrogen gas, carbon dioxide, air, propane, butane, pentane, cyclopentane, hexane, dichloroethane, dichlorodifluoromethane, dichloromonofluoromethane, and trichloromonofluoromethane. These may be used alone or in combination of two or more. The physical foaming agent can be used in any of a liquid state, a supercritical state, and a gas state.

  Examples of the chemical foaming agent include baking soda; a mixture of baking soda and an organic acid such as citric acid, sodium citrate, and stearic acid; an isocyanate compound such as tolylene diisocyanate and 4,4′-diphenylmethane diisocyanate; Azo or diazo compounds such as azobisbutyronitrile, barium azodicarboxylate, diazoaminobenzene, trihydrazinotriazine; hydrazine derivatives such as benzenesulfonyl hydrazide, p, p'-oxybis (benzenesulfonyl hydrazide), toluenesulfonyl hydrazide Nitroso compounds such as N, N′-dinitrosopentamethylenetetramine and N, N′-dimethyl-N, N′-dinitrosotephthalamide; p-toluenesulfonyl semicarbazide, 4,4 ′ Semicarbazide compounds such oxybisbenzenesulfonyl semicarbazide, azide compounds, and triazole compounds. These may be used alone or in combination of two or more.

In addition to the foaming agent, zinc oxide, urea, or the like may be used as a foaming aid, and talc, zinc stearate, calcium silicate, or the like may be used as a foam regulator.
The amount of the foaming agent to be added is not particularly limited because it varies depending on the type of foaming agent, the molding method, or the target foaming ratio, but it is generally 0.1% relative to 100 parts by weight of the propylene-based resin composition for foamed molded products. 1 to 50 parts by weight, preferably 1 to 20 parts by weight.

[Foamed molded product]
The foam molded article obtained by foam molding of the propylene-based resin composition for foam molded article of the present invention is excellent in balance between heat resistance and mechanical strength, flexibility and recoverability after deformation.

  Accordingly, the foamed molded article of the present invention is excellent in weather resistance, chemical resistance, processability, hygiene, and recyclability, and is used for automobile interior materials, heat insulating materials, civil engineering / architectural joint materials, sound absorbing materials, and sports equipment. Alternatively, it can be widely used as a cushioning material for food packaging, a heat insulating material for air conditioning equipment, and the like.

  Next, examples of the propylene-based resin composition for foamed molded products and the foamed molded products of the present invention will be described in more detail with reference to examples, but the present invention is not limited thereto.

≪Differential scanning calorimetry≫
The melting peak temperature of the propylene-based resin composition is a value determined in accordance with JIS K7121 using Diamond DSC (manufactured by Perkin-Elmer), measured under the following conditions under a nitrogen stream, and the following (3 ) To determine the melting peak temperature.
(1) The temperature is raised to 230 ° C. at a rate of 500 ° C./min, and the sample is once melted and held for 10 minutes.
(2) The temperature is lowered to 30 ° C. at a rate of 10 ° C./min and held for 1 minute.
(3) The temperature is raised from 30 ° C. to 230 ° C. at a rate of 10 ° C./min.

  Further, the melting energy of 140 ° C. or higher of the propylene-based resin composition is measured under the same conditions as the above-described melting peak temperature measurement, and is 140 ° C. or higher of the melting energy obtained from the total melting peak area according to JIS K7122. This is a value corresponding to the melting energy obtained from the melting peak area.

≪Temperature rise elution fractionation≫
The temperature rising elution fractionation of the propylene resin composition was measured under the following conditions.
Column: 4.2 mmφ × 150 mm (made of stainless steel)
Filler: Chromosolv P (30-60 mesh)
Solvent: o-dichlorobenzene Flow rate: 1.0 ml / min Sample concentration: 6 mg / ml
Sample injection volume: 0.5 ml
Crystallization: The temperature is lowered from 135 ° C. to 0 ° C. at a rate of 5 ° C./hr and held for 30 minutes.
Elution: The temperature is raised from 0 ° C to 135 ° C at a rate of 40 ° C / hr.
Detector: IR (manufactured by MIRAN, detection wavelength 3.41 μm)

≪Melt flow rate (MFR) ≫
The MFR of the propylene-based resin composition was measured in accordance with JIS K7210 (230 ° C., load 2.16 kg).

≪Foaming ratio≫
The specific gravity of the foamed molded product was measured by an underwater substitution method, and the foaming ratio was calculated.
≪Compression hardness≫
After measuring the thickness of a rectangular parallelepiped test piece having a length of 10 mm, a width of 10 mm, and a thickness of about 10 mm, the test piece was placed in a compression tester and compressed by 25% of the initial thickness at a speed of 10 mm / min. The stress was calculated from the load after 20 seconds to obtain the compression hardness.

≪25% compression strain≫
The thickness of a rectangular parallelepiped test piece having a length of 10 mm, a width of 10 mm, and a thickness of about 10 mm was measured, and this was designated as t0. Next, the test piece was placed in a compression tester, and was compressed and fixed by 25% of the initial thickness of the test piece at a speed of 10 mm / min. The thickness at this time was defined as t1. The sample was allowed to stand at 23 ° C. for 22 hours, then released from compression, and allowed to stand at 23 ° C. for 24 hours. The thickness of the test piece was measured, and the thickness was defined as t2. (T0−t2) / (t0−t1) × 100 (%) was defined as 25% compression strain.

≪Tensile test≫
A test piece punched with a small dumbbell punching die (total length: 50 mm, parallel part length: 30 mm, parallel part width: 5 mm, chuck part width 10 mm) is attached to a tensile tester with a chuck distance of 30 mm, and a tensile speed of 10 mm / min. The tensile strength at break and the tensile elongation at break were calculated from the maximum load until pulling and cutting and the distance between chucks at the time of cutting.

[Production Example 1]
(1) Preparation of solid catalyst component In a catalytic reaction tank made of stainless steel having an internal volume of 500 L, sufficiently substituted with nitrogen gas, 16 kg of diethoxymagnesium, 80 L of purified heptane, 2.4 L of silicon tetrachloride, and diethyl phthalate 3L was charged. While keeping the inside of the catalyst reaction tank at 90 ° C., 77 L of titanium tetrachloride was added with stirring and reacted at 110 ° C. for 2 hours, and then the solid component was separated and washed with purified heptane at 80 ° C. Further, 122 L of titanium tetrachloride was added and reacted at 110 ° C. for 2 hours, and then sufficiently washed with purified heptane to obtain a solid catalyst component.

(2) Prepolymerization Into an 80 L stainless steel polymerization reaction tank sufficiently substituted with nitrogen gas, 4 kg of the solid catalyst component obtained in (1) above, 40 L of purified heptane, 1.6 mol of triethylaluminum, and cyclohexylmethyl Dimethoxysilane 0.4 mol was charged. While maintaining the inside of the polymerization reaction vessel at 40 ° C., propylene was continuously supplied for 2 hours with stirring, and prepolymerization was performed at almost normal pressure. After the supply of propylene was stopped, the inside of the polymerization reaction tank was kept at 40 ° C. for 30 minutes, and then sufficiently washed with purified heptane to obtain a prepolymerized catalyst.

(3) Polymerization Into a stainless steel polymerization reactor equipped with a stirrer with an internal volume of 5 L, sufficiently substituted with nitrogen gas, 3 L of liquid propylene, 1.7 mmol of triethylaluminum, 0.17 mmol of cyclohexylmethyldimethoxysilane, and hydrogen in the gas phase The concentration in the polymerization reaction vessel was increased to 55 ° C. Next, 0.011 mmol of the prepolymerized catalyst obtained in the above (2) was added in terms of titanium atom, and propylene polymerization was performed at 55 ° C. for 30 minutes (step 1). Next, ethylene was supplied in such an amount that the pressure in the gas phase was 0.16 MPa, and propylene / ethylene copolymerization was performed at 55 ° C. for 100 minutes (step 2). After completion of the reaction, the temperature was lowered and the unreacted monomer was purged to obtain a polymer (A) which is a block copolymer containing a polypropylene component and a propylene / ethylene random copolymer component. The obtained polymer (A) was dried at 70 ° C. for 1 hour. As a result of collecting and analyzing a part of this polymer (A), the MFR was 0.05 g / 10 min, and the content of structural units derived from ethylene was 30 mol%.

[Production Example 2]
With respect to 100 parts by weight of the polymer (A) obtained in Production Example 1, 0.2 part by weight of Irganox 1010 (manufactured by Ciba Specialty Chemicals) as an antioxidant and DHT-4A (manufactured by Kyowa Chemical Co., Ltd.) as a stabilizer ) 0.05 part by weight, and 1.2 parts by weight of Perhexa 25B-40 (manufactured by Nippon Oil &Fats; purity 40%) as a peroxide as a decomposing agent were blended and sufficiently mixed with stirring. Next, using a KZW31 twin screw extruder (manufactured by Technobel, screw diameter 31 mm, L / D = 30), kneading is performed at a cylinder temperature of 240 ° C., a die temperature of 200 ° C., a screw rotation speed of 300 rpm, and an extrusion rate of 16 kg / h. A polymer (B) was obtained. MFR of the obtained polymer (B) was 75 g / 10 minutes.

[Production Example 3]
(1) Preparation of the solid catalyst component and (2) prepolymerization were carried out under the same conditions as in Production Example 1.

(3) Polymerization Into a stainless steel polymerization reactor equipped with a stirrer with an internal volume of 5 L, sufficiently substituted with nitrogen gas, 3 L of liquid propylene, 1.7 mmol of triethylaluminum, 0.17 mmol of cyclohexylmethyldimethoxysilane, and hydrogen in the gas phase The temperature in the polymerization reaction vessel was raised to 55 ° C. Next, 0.011 mmol of the prepolymerized catalyst obtained in the above (2) was added in terms of titanium atom, and propylene polymerization was performed at 55 ° C. for 30 minutes (step 1). Next, ethylene was supplied in such an amount that the pressure in the gas phase became 0.23 MPa, and propylene / ethylene copolymerization was performed at 55 ° C. for 100 minutes (step 2). After completion of the reaction, the temperature was lowered and the unreacted monomer was purged to obtain a polymer (C) which is a block copolymer containing a polypropylene component and a propylene / ethylene random copolymer component. The obtained polymer (C) was dried at 70 ° C. for 1 hour. As a result of collecting and analyzing a part of this polymer (C), the MFR was 0.03 g / 10 min, and the content of the structural unit derived from ethylene was 40 mol%.

[Production Example 4]
In Production Example 2, 100 parts by weight of the polymer (C) obtained in Production Example 3 was used in place of 100 parts by weight of the polymer (A) obtained in Production Example 1, and Perhexa 25B-40 as a peroxide was used. A polymer (D) was obtained in the same manner as in Production Example 2, except that the blending amount (made by Nippon Oil &Fats; purity 40%) was changed to 0.02 parts by weight. MFR of the obtained polymer (D) is 2.0 g /
It was 10 minutes.

[Production Example 5]
In Production Example 2, instead of 100 parts by weight of the polymer (A) obtained in Production Example 1, 60 parts by weight of the polymer (A) obtained in Production Example 1 and 40 parts by weight of the polymer (C) obtained in Production Example 3 In the same manner as in Production Example 2 except that the amount of Perhexa 25B-40 (manufactured by Nippon Oil &Fats; purity 40%) as a peroxide was changed to 0.25 parts by weight. ) MFR of the obtained polymer (E) was 10 g / 10 minutes.
Table 1 shows the compositions of the polymers (A) to (E) obtained in Production Examples 1 to 5.

［実施例１］
ポリマー（Ａ）３０重量部、ポリマー（Ｂ）５０重量部、およびポリマー（Ｄ）２０重量部と、酸化防止剤としてイルガノックス１０１０（チバスペシャリティーケミカルズ社製）０．１重量部、イルガフォス１６８（チバスペシャリティーケミカルズ社製）０．１
重量部、およびステアリン酸カルシウム（日本油脂製）０．１重量部とをヘンシェルミキサーで攪拌混合した。次に、ＫＺＷ３１二軸押出機（テクノベル製、スクリュー径３１ｍｍ、Ｌ／Ｄ＝３０）を用い、シリンダー温度１９０℃、ダイス温度１９０℃、スクリュー回転数１５０ｒｐｍ、押出量１５ｋｇ／ｈで混練してプロピレン系樹脂組成物を得た。得られたプロピレン系樹脂組成物は、融解ピーク温度が１５２．７℃、融解ピーク面積から得られる１４０℃以上の融解エネルギーが５．３ｍＪ／ｍｇ、ＴＲＥＦによって得られる溶出曲線において、溶出温度８０℃以上における溶出成分量が全溶出成分量の１１．３重量％、ＭＦＲが１．９ｇ／１０分であった。

[Example 1]
30 parts by weight of polymer (A), 50 parts by weight of polymer (B), 20 parts by weight of polymer (D), 0.1 part by weight of Irganox 1010 (manufactured by Ciba Specialty Chemicals) as an antioxidant, and Irgafos 168 ( Ciba Specialty Chemicals) 0.1
Part by weight and 0.1 part by weight of calcium stearate (manufactured by NOF Corporation) were stirred and mixed with a Henschel mixer. Next, using a KZW31 twin-screw extruder (manufactured by Technobel, screw diameter 31 mm, L / D = 30), kneading at a cylinder temperature of 190 ° C., a die temperature of 190 ° C., a screw speed of 150 rpm, and an extrusion rate of 15 kg / h, propylene A system resin composition was obtained. The resulting propylene-based resin composition has a melting peak temperature of 152.7 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 5.3 mJ / mg, and an elution temperature of 80 ° C. in an elution curve obtained by TREF. The amount of eluted components in the above was 11.3% by weight of the total amount of eluted components, and the MFR was 1.9 g / 10 minutes.

  Next, the propylene from the raw material supply hopper of a tandem short-axis extruder (first stage extruder screw diameter: 35 mm, cylinder set temperature: 240 ° C., second stage extruder screw diameter: 50 mm, cylinder set temperature: 150 ° C.) After supplying the resin resin composition at 12 kg / h to melt, carbon dioxide in a supercritical state from the middle of the first stage extruder is in a proportion of 4.2 parts by weight with respect to 100 parts by weight of the propylene resin composition. Press-fitted with. Subsequently, the foamable propylene resin composition is extruded from a perforated die (set temperature: 150 ° C.) having 27 holes with a diameter of 0.8 mm attached to the tip of the second stage extruder. As a result, a prismatic extruded foam molded body in which foam strands were gathered was obtained.

  The specific gravity of the extruded foamed molded product was measured by an underwater substitution method, and the expansion ratio was calculated. Further, a test piece having a length of 10 mm, a width of 10 mm, and a thickness of 10 mm was cut out from the extruded foamed product, and the compression hardness and 25% compression strain were measured. The results are shown in Table 2.

[Example 2]
The resin component was added to 30 parts by weight of polymer (A), 20 parts by weight of polymer (B), 20 parts by weight of polymer (D), and 30 parts by weight of homopolypropylene (X) (Prime Polypro J139) having an MFR of 60 g / 10 min. A propylene-based resin composition was obtained in the same manner as Example 1 except for changing. The resulting propylene-based resin composition has a melting peak temperature of 161.9 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 36.2 mJ / mg, and an elution temperature of 80 ° C. in an elution curve obtained by TREF. The amount of eluted components in the above was 36.5% by weight of the total amount of eluted components, and the MFR was 1.7 g / 10 minutes.
Next, in the same manner as in Example 1, an extruded foam molded article was obtained from the propylene-based resin composition.
Table 2 shows the expansion ratio, compression hardness, and 25% compression strain of the extruded foam molding.

[Example 3]
A propylene-based resin composition was obtained in the same manner as in Example 1 except that the resin component was changed to 100 parts by weight of the polymer (A). The resulting propylene-based resin composition has a melting peak temperature of 150.3 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 5.4 mJ / mg, and an elution temperature of 80 ° C. in an elution curve obtained by TREF. The amount of eluted components in the above was 16.4% by weight of the total amount of eluted components, and the MFR was 0.35 g / 10 minutes.
Next, in the same manner as in Example 1, an extruded foam molded article was obtained from the propylene-based resin composition.
Table 2 shows the expansion ratio, compression hardness, and 25% compression strain of the extruded foam molding.

[Comparative Example 1]
A propylene-based resin composition was obtained in the same manner as in Example 1 except that the resin component was changed to 30 parts by weight of polymer (A), 20 parts by weight of polymer (D), and 50 parts by weight of homopolypropylene (X). The resulting propylene resin composition has a melting peak temperature of 163.3 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 55.7 mJ / mg, and an elution temperature of 80 ° C. in an elution curve obtained by TREF. The amount of eluted components in the above was 51.7% by weight of the total amount of eluted components, and the MFR was 2.8 g / 10 minutes.
Next, in the same manner as in Example 1, an extruded foam molded article was obtained from the propylene-based resin composition.
Table 2 shows the expansion ratio, compression hardness, and 25% compression strain of the extruded foam molding.

[Comparative Example 2]
As a propylene-based resin composition, the melting peak temperature is 156.9 ° C., the melting energy of 140 ° C. or higher obtained from the melting peak area is 85.8 mJ / mg, and the elution curve obtained by TREF is eluted at an elution temperature of 80 ° C. or higher. Extruded foamed molded article in the same manner as in Example 1 using homopolypropylene (Y) (Prime Polypro E-105PW) having a component amount of 85.9% by weight and a MFR of 3.3 g / 10 min. Got.
Table 2 shows the expansion ratio, compression hardness, and 25% compression strain of the extruded foam molding.

表２からわかるように、本発明の発泡成形体用プロピレン系樹脂組成物から得られる発泡成形体（実施例１〜３）は、１４０℃以上の融解エネルギーが５０ｍＪ／ｍｇ以上で、ＴＲＥＦの溶出温度８０℃以上における溶出成分量が全溶出成分量の５０重量％を超えているプロピレン系樹脂組成物（比較例１〜２）から得られる発泡成形体と比較して、２５％圧縮歪が小さいので、変形後の回復性に優れている。

As can be seen from Table 2, the foamed molded products (Examples 1 to 3) obtained from the propylene-based resin composition for foamed molded products of the present invention have a melting energy of 140 ° C. or higher and 50 mJ / mg or higher, and TREF elution. 25% compression strain is small as compared with foamed molded products obtained from propylene-based resin compositions (Comparative Examples 1 and 2) in which the amount of the eluted component at a temperature of 80 ° C. or higher exceeds 50% by weight of the total eluted component Therefore, it has excellent recoverability after deformation.

[Example 4]
Polymer component (A) 18 parts by weight, polymer (B) 30 parts by weight, polymer (D) 1
A propylene-based resin composition was obtained in the same manner as in Example 1 except that 2 parts by weight and 40 parts by weight of the polymer (E) were changed. The resulting propylene resin composition has a melting peak temperature of 156.6 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 7.9 mJ / mg, and an elution temperature of 80 ° C. in an elution curve obtained by TREF. The amount of eluted components in the above was 14.1% by weight of the total amount of eluted components, and the MFR was 3.4 g / 10 minutes.

  Next, 100 parts by weight of the propylene-based resin composition and 0.5 parts by weight of chemical blowing agent master batch Polyslene EE205 (bicarbonate / citric acid, manufactured by Eiwa Chemical Industries) were dry blended to obtain a raw material composition. A twin screw extruder (screw diameter: 41 mm, L / D = 28) connected with a ring die (die diameter: 65 mm, die lip interval: 0.8 mm, set temperature: 180 ° C.) via a gear pump (set temperature: 180 ° C.) The cylinder composition temperature: C1-C3 = 210 ° C., C4-C6 = 180 ° C.) The raw material composition is supplied at 30 kg / h from the raw material supply hopper, and liquefied carbon dioxide is supplied from the C4 portion of the extruder. Press-fitting was performed at a ratio of 0.4 part by weight to 100 parts by weight of the composition. The cylindrical resin extruded from the ring die was divided into two on a cooling mandrel having an outer diameter of 207 mm and wound up by a take-up machine to obtain a foamed sheet having a thickness of 1.3 mm and a width of 740 mm.

  The specific gravity of the foam sheet was measured by an underwater substitution method, and the expansion ratio was calculated. In addition, 8 foam sheets each having a length of 10 mm and a width of 10 mm were overlapped and adjusted to a thickness of about 10 mm, and compression hardness and 25% compression strain were measured. The results of the tensile test are shown together in Table 3.

[Example 5]
The resin component is 14 parts by weight of polymer (A), 24 parts by weight of polymer (B), 10 parts by weight of polymer (D), 32 parts by weight of polymer (E), and polypropylene for foaming having an MFR of 4.8 g / 10 minutes ( (FB3312; manufactured by Nippon Polypro) A propylene-based resin composition was obtained in the same manner as in Example 4 except that the amount was changed to 20 parts by weight. The resulting propylene-based resin composition has a melting peak temperature of 161.5 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 27.5 mJ / mg, and an elution curve obtained by TREF with an elution temperature of 80 ° C. The amount of eluted components in the above was 28.6% by weight of the total amount of eluted components, and the MFR was 3.6 g / 10 minutes.
Next, a foamed sheet was obtained from the propylene resin composition in the same manner as in Example 4.
Table 3 shows the expansion ratio, the tensile test result, the compression hardness, and the 25% compression strain of the foam sheet.

[Example 6]
A propylene-based resin composition was obtained in the same manner as in Example 4 except that the resin component was changed to 30 parts by weight of the polymer (A), 40 parts by weight of the polymer (B), and 30 parts by weight of the polymer (E). The resulting propylene-based resin composition has a melting peak temperature of 153.8 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 6.5 mJ / mg, and an elution temperature of 80 ° C. in an elution curve obtained by TREF. The amount of eluted components in the above was 10.0% by weight of the total amount of eluted components, and the MFR was 2.0 g / 10 minutes.
Next, a foamed sheet was obtained from the propylene resin composition in the same manner as in Example 4.
Table 3 shows the expansion ratio, the tensile test result, the compression hardness, and the 25% compression strain of the foam sheet.

[Example 7]
A propylene-based resin composition was obtained in the same manner as in Example 4 except that the resin component was changed to 60 parts by weight of the polymer (D) and 40 parts by weight of polypropylene for foaming (FB3312). The resulting propylene-based resin composition has a melting peak temperature of 161.8 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 43.2 mJ / mg, and an elution temperature of 80 ° C. in an elution curve obtained by TREF. The amount of eluted components in the above was 48.6% by weight of the total amount of eluted components, and the MFR was 3.1 g / 10 minutes.
Next, a foamed sheet was obtained from the propylene resin composition in the same manner as in Example 4.
Table 3 shows the expansion ratio, the tensile test result, the compression hardness, and the 25% compression strain of the foam sheet.

[Comparative Example 3]
Example 4 except that the resin component was changed to 20 parts by weight of foaming polypropylene (FB3312) and 80 parts by weight of homopolypropylene (Z) (Prime Polypropylene F-704NT) having an MFR of 7 g / 10 min. A propylene-based resin composition was obtained. The resulting propylene-based resin composition has a melting peak temperature of 162.1 ° C., a melting energy of 140 ° C. or higher obtained from the melting peak area of 90.3 mJ / mg, and an elution curve obtained by TREF with an elution temperature of 80 ° C. The amount of eluted components in the above was 87.3% by weight of the total amount of eluted components, and the MFR was 7.2 g / 10 minutes.

Next, a foamed sheet was obtained from the propylene resin composition in the same manner as in Example 4.
Table 3 shows the expansion ratio, the tensile test result, the compression hardness, and the 25% compression strain of the foam sheet.

表３からわかるように、本発明の発泡成形体用プロピレン系樹脂組成物から得られる発泡シート（実施例４〜７）は、１４０℃以上の融解エネルギーが５０ｍＪ／ｍｇ以上で、ＴＲＥＦの溶出温度８０℃以上における溶出成分量が全溶出成分量の５０重量％を超えているプロピレン系樹脂組成物（比較例３）から得られる発泡シートと比較して、引張破断伸び（％）が大きく、２５％圧縮歪が小さいので、柔軟で変形後の回復性に優れている。

As can be seen from Table 3, the foamed sheets (Examples 4 to 7) obtained from the propylene-based resin composition for foamed molded products of the present invention have a melting energy of 140 mC or higher and 50 mJ / mg or higher, and the elution temperature of TREF. Compared with the foamed sheet obtained from the propylene-based resin composition (Comparative Example 3) in which the amount of the eluted component at 80 ° C. or higher exceeds 50% by weight of the total eluted component amount, the elongation at break (%) is large, 25 Since% compression strain is small, it is flexible and excellent in recoverability after deformation.

The foam molded product obtained by foaming the propylene-based resin composition part of the present invention has a good balance of heat resistance, mechanical strength, extensibility, flexibility, and recoverability after deformation, and is a problem with polyurethane foam molded products. Therefore, it can be used very advantageously in applications such as interior materials, heat insulating materials, joint materials, sound absorbing materials, and cushioning materials.

Claims (8)

A propylene-based resin composition comprising at least one selected from the group consisting of a propylene homopolymer and a propylene / α-olefin copolymer,
The melting peak temperature (Tm) measured by a differential scanning calorimeter (DSC) is in the range of 140 to 165 ° C., and the melting energy of 140 ° C. or higher obtained from the melting peak area is less than 50 mJ / mg,
A propylene-based resin composition for foam molded articles, wherein an elution component amount at an elution temperature of 80 ° C. or higher is 50% by weight or less of a total elution component amount in an elution curve obtained by temperature rising elution fractionation (TREF).   The melt flow rate (MFR; JIS K7210, 230 ° C, load 2.16 kg) is in the range of 0.01 to 30 g / 10 minutes, and the propylene-based resin composition for foam molded articles according to claim 1 .   The propylene-based resin composition for foam molded articles according to claim 1 or 2, wherein the α-olefin is ethylene. (I) a propylene homopolymer or a propylene / α-olefin copolymer having a melting peak temperature in the range of 140 to 165 ° C .;
(Ii) a propylene homopolymer or a propylene / α-olefin copolymer having no melting peak temperature or less than 140 ° C. and having a melting energy in the range of 0 to 30 mJ / mg;
The propylene-based resin composition for foam molded articles according to any one of claims 1 to 3, wherein The content of the structural unit derived from the α-olefin of the propylene / α-olefin copolymer in (i) is more than 0 mol% and 10 mol% or less, and the propylene / α-olefin copolymer in (ii) The content of the structural unit derived from α-olefin is more than 10 mol% and 80 mol% or less.
The propylene-based resin composition for foam molded articles according to claim 4. A foamed molded product obtained by foaming the propylene-based resin composition for foamed molded product according to any one of claims 1 to 5 . A foam molded article obtained by extrusion foaming the propylene-based resin composition for a foam molded article according to any one of claims 1 to 5. A method for producing a foam molded article, comprising subjecting the propylene-based resin composition for foam molded article according to any one of claims 1 to 5 to extrusion foam molding.