JP7506464B2 - Polypropylene resin composition for automobile interior materials and molded body for automobile interior parts - Google Patents

Description

The present invention relates to a polypropylene resin composition for automobile interior materials and a molded article for automobile interior parts obtained by molding the same.

Automotive interior materials are made by molding resin compositions made from polypropylene resin with inorganic fillers and rubber added, but it is desirable that dust does not adhere to the interior materials after molding or when they are delivered to the user. Since dust adhesion is mainly caused by static electricity, it is common to add antistatic agents to reduce the electrical resistance of the interior material surface and allow static electricity to escape in order to prevent dust adhesion.

However, if the amount of antistatic agent added is increased in order to improve antistatic performance, the antistatic agent will vaporize when the temperature inside the vehicle rises in the summer, for example, and adhere to the windshield, causing a problem known as fogging, in which the transparency of the glass is impaired. For this reason, automotive interior materials are required to be free of dust adhesion to their surfaces, and furthermore, to ensure that the transparency of the vehicle's glass is not impaired by the adhesion of the antistatic agent.

Patent Document 1 discloses a resin composition for automotive interior materials with excellent antistatic properties and antifogging properties, which is characterized by comprising a mixture of 30 to 82 parts by weight of a propylene-ethylene block copolymer (component A) containing 5 to 20% by weight of a propylene-ethylene random copolymer portion with an ethylene content of 25 to 75% by weight, 10 to 40 parts by weight of talc (component B), and 8 to 30 parts by weight of an olefin-based elastomer (component C) totaling 100 parts by weight, with the total of components B and C being 20 to 60 parts by weight, and incorporating 0.3 to 0.45% by weight of an antistatic agent (component D) consisting of a mixture of monoglycerin fatty acid ester, diglycerin fatty acid ester, and alkyldiethanolamine, based on the composition.

Patent Document 2 discloses a polypropylene resin composition that contains (A) 50 to 90 parts by weight of crystalline polypropylene resin, (B) 10 to 50 parts by weight of inorganic filler, (C) 0 to 40 parts by weight of rubber (wherein the total amount of components (A), (B) and (C) is 100 parts by weight), and (D) 0.01 to 3 parts by weight of palmitic acid diethanolamide.

Patent Document 3 discloses a polypropylene resin composition containing 100 parts by weight of a propylene polymerization material, 0.1 to 0.4 parts by weight of at least one ester compound selected from the group consisting of fatty acid esters of monoglycerin and fatty acid esters of diglycerin, 0.2 to 0.8 parts by weight of an antistatic agent containing 0.1 to 0.4 parts by weight of stearyl diethanolamine monostearate, 0.01 to 0.4 parts by weight of N,N'-di(hydroxyethyl)alkylamide, and 0.01 to 0.3 parts by weight of a hindered amine-based light stabilizer.

Patent Document 4 discloses an automobile interior material made of a resin composition in which 100 parts by weight of polyolefin is mixed with 0.001 to 10 parts by weight of an alkyl phosphate metal salt and 0.001 to 10 parts by weight of a hindered amine compound (B).

Japanese Patent Application Laid-Open No. 11-323070 JP 2002-212353 A JP 2014-201615 A JP 2000-136271 A

However, the polypropylene resin compositions described in the above Patent Documents 1 to 3 do not have sufficient fogging prevention properties, and the emission amounts of volatile organic compounds (VOCs), particularly aldehydes such as acetaldehyde and formaldehyde, are not satisfactory.
On the other hand, the polyolefin resin composition described in Patent Document 4 above does not have sufficient antistatic properties, and has a problem of cloudiness due to bleed-out.
The present invention aims to solve the problems in the conventional art as described above, and aims to provide a polypropylene resin composition that suppresses fogging and the generation of aldehydes without impairing antistatic properties.

As a result of extensive research into solving the above problems, the inventors discovered that the use of a specific phosphate ester compound provides sufficient antistatic effects while also significantly suppressing fogging and the generation of aldehydes, leading to the completion of the present invention.

（式中、Ｒは炭素数１～２４のアルキル基、炭素数２～２４のアルケニル基又は置換基を有していてもよいアリール基であり、ＡＯは炭素数２～４のオキシアルキレン基であり、ｎはアルキレンオキサイドの平均付加モル数であって１～１０の数であり、ｍは１～３の整数であり、Ｍは水素原子、アルカリ金属、第２族金属、アンモニウム基、または有機アンモニウム基である。）
を配合してなる自動車内装材用ポリプロピレン系樹脂組成物。
［２］ポリプロピレン系樹脂（Ａ）１００質量部に対し、さらに多価アルコール脂肪酸エステル（Ｃ）を０．０１～２．０質量部を配合してなる、［１］に記載の自動車内装材用ポリプロピレン系樹脂組成物。
［３］前記（Ｂ）、及び（Ｃ）成分を合計で０．０１～２．０質量部配合してなる、［２］に記載の自動車内装材用ポリプロピレン系樹脂組成物。
［４］前記（Ｂ）成分と、（Ｃ）成分の合計との質量比が、（Ｂ）／（Ｃ）＝１００／０～１／９９である、［１］～［４］に記載の自動車内装材用ポリプロピレン系樹脂組成物。
［５］［１］～［４］に記載のポリプロピレン系樹脂組成物を成形してなる自動車内装部品用成形体。 That is, the present invention is as follows.
[1] For 100 parts by mass of polypropylene-based resin (A),
0.01 to 2.0 parts by mass of a phosphoric acid ester compound (B) represented by the following chemical formula (1):

(In the formula, R is an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, or an aryl group which may have a substituent; AO is an oxyalkylene group having 2 to 4 carbon atoms; n is the average number of moles of alkylene oxide added which is a number from 1 to 10; m is an integer from 1 to 3; and M is a hydrogen atom, an alkali metal, a Group 2 metal, an ammonium group, or an organic ammonium group.)
A polypropylene resin composition for automobile interior materials comprising:
[2] The polypropylene-based resin composition for automobile interior materials according to [1], further comprising 0.01 to 2.0 parts by mass of a polyhydric alcohol fatty acid ester (C) per 100 parts by mass of the polypropylene-based resin (A).
[3] The polypropylene resin composition for automobile interior materials according to [2], comprising 0.01 to 2.0 parts by mass of the (B) and (C) components in total.
[4] The polypropylene resin composition for automobile interior materials according to any one of [1] to [4], wherein a mass ratio of the component (B) to the total of the component (C) is (B)/(C)=100/0 to 1/99.
[5] A molded article for automobile interior parts obtained by molding the polypropylene resin composition according to any one of [1] to [4].

The polypropylene resin composition for automobile interior materials of the present invention and the molded article for automobile interior parts obtained by molding the same can significantly suppress the generation of fogging and aldehydes while maintaining the antistatic properties necessary to prevent adhesion of dust, etc. In addition, since the composition does not cause cloudiness due to bleed-out, it can be preferably used as an automobile interior part.

The present invention will be described in detail below.
As the polypropylene resin (A) constituting the polypropylene resin composition of the present invention, a conventionally known polypropylene resin can be appropriately selected and used. Examples of such polypropylene resin (A) include propylene homopolymers, propylene-α-olefin random copolymers and propylene block copolymers of propylene and α-olefins other than propylene. The polypropylene resin (A) may also be modified with a polar group-containing monomer such as maleic anhydride. The polypropylene resin (A) may be used alone or in combination of two or more.

Preferred polypropylene resins (A) include propylene homopolymers, propylene-α-olefin random copolymers containing 30% by weight or less, preferably 5% by weight or less, of other α-olefin units, and propylene block copolymers having an n-decane extractable amount of 10% by weight or less, particularly 8% by weight or less. Note that "α-olefin units" refer to structural units derived from α-olefins that constitute a polymer. In the present invention, α-olefins include ethylene.

Preferably, the other α-olefins forming the propylene-α-olefin random copolymer or propylene block copolymer are α-olefins having 2 to 20 carbon atoms other than propylene, and specific examples thereof include ethylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-hexadecene, and 4-methyl-1-pentene. These α-olefins can be used alone or in combination of two or more.

A propylene block copolymer is usually obtained by producing a propylene homopolymer in a first-stage polymerization vessel and producing a propylene-α-olefin random copolymer rubber (typically a propylene-ethylene random copolymer rubber) in the presence of the propylene homopolymer in a second-stage polymerization vessel in a series-connected multiple polymerization vessels, and the propylene homopolymer and the propylene-α-olefin random copolymer rubber are mixed uniformly. When a propylene block copolymer is used as the polypropylene resin (A), if there is a sufficient amount of copolymer rubber in the propylene block copolymer, the incorporation of the rubber component can be omitted.

The polypropylene resin (A) used in the present invention can be produced by a known method using a solid titanium catalyst or a metallocene catalyst that is known per se.

The polypropylene resin (A) has a melt flow rate MFR (230°C, under a load of 2.16 kg) measured in accordance with ASTM D1238, which is usually 0.1 to 300 g/10 min, preferably 1 to 100 g/10 min, and more preferably 50 g/10 min.

The phosphate ester compound (B) used in the present invention is a compound represented by the following general formula (1):

（式中、Ｒは炭素数１～２４のアルキル基、炭素数２～２４のアルケニル基又は置換基を有していてもよいアリール基であり、ＡＯは炭素数２～４のオキシアルキレン基であり、ｎはアルキレンオキサイドの平均付加モル数であって１～１０の数でありであり、ｍは１～３の整数であり、Ｍは水素原子、アルカリ金属、第２族金属、アンモニウム基、または有機アンモニウム基である。）

(In the formula, R is an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, or an aryl group which may have a substituent; AO is an oxyalkylene group having 2 to 4 carbon atoms; n is the average number of moles of alkylene oxide added and is a number from 1 to 10; m is an integer from 1 to 3; and M is a hydrogen atom, an alkali metal, a Group 2 metal, an ammonium group, or an organic ammonium group.)

Specific examples of the alkyl group having 1 to 24 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, a cyclopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, an n-pentyl group, a neopentyl group, a cyclopentyl group, an n-hexyl group, a cyclohexyl group, an n-octyl group, an n-decyl group, a 1-adamantyl group, a dodecyl group (lauryl group), a tridecyl group, a tetradecyl group (myrstil group), a hexadecyl group (palmityl group), an octadecyl group (stearyl group), an icosyl group, a docosyl group (behenyl group), and a tetracosyl group.
Specific examples of alkenyl groups having 2 to 24 carbon atoms include ethenyl, propenyl, butenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, eicosenyl, docosenyl, and tetracosenyl groups, which may have a branched or cyclic structure.
Examples of the aryl group which may have a substituent include unsubstituted aryl groups such as a phenyl group, a tolyl group, a xylyl group, a cumenyl group, a mesityl group, a biphenyl group, and a naphthyl group, and the above-mentioned aryl groups which have a substituent such as a hydrocarbon group having 1 to 24 carbon atoms, an alkyl group having 1 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, and an alkoxy group having 2 to 10 carbon atoms.
Among these, from the viewpoint of imparting appropriate bleeding properties, alkyl or alkenyl groups having 8 to 22 carbon atoms are preferred.

In the general formula (1), AO is an oxyalkylene group having 2 to 4 carbon atoms, specifically an oxyethylene group, a 1,2- or 1,3-oxypropylene group, and a 1,2-, 1,3-, or 1,4-oxybutylene group. Among these, preferred are an oxyethylene group and a 1,2-oxypropylene group, and particularly preferred is an oxyethylene group. n is the average number of moles of alkylene oxide added, and is a number from 1 to 10, but is preferably a number from 1 to 6 from the viewpoint of antistatic effect. When n is 2 or more, n AO may be the same or different, and when different, -(AO) _n - may be any of the addition forms of random addition, block addition, or alternating addition. m is an integer from 1 to 3, and is preferably 1 or 2.

In the general formula (1), M is a hydrogen atom, an alkali metal, a Group 2 metal, an ammonium group, or an organic ammonium group. Examples of alkali metals include lithium (Li), sodium (Na), and potassium (K), and examples of Group 2 metals include beryllium (Be), magnesium (Mg), calcium (Ca), strontium (Sr), and barium (Ba). The organic ammonium group is an ammonium group derived from an organic amine, and examples of the organic amine include alkanolamines such as monoethanolamine, diethanolamine, and triethanolamine, methylamine, dimethylamine, triethylamine, ethylamine, diethylamine, and triethylamine. Among these Ms, a hydrogen atom is preferred.

In the polypropylene resin composition for automotive interior materials of the present invention, the amount of the phosphate ester compound (B) is 0.01 to 2.0 parts by mass per 100 parts by mass of the polypropylene resin (A), but from the viewpoint of antistatic effect, it is preferably 0.05 to 0.5 parts by mass, and more preferably 0.1 to 0.4 parts by mass.

The polypropylene resin composition for automotive interior materials of the present invention can contain a polyhydric alcohol fatty acid ester (C) as necessary to enhance the antistatic effect. The polyhydric alcohol fatty acid ester (C) is an ester compound obtained by a known method such as an esterification reaction between a polyhydric alcohol and a fatty acid, or an ester exchange reaction between a polyhydric alcohol and a fatty acid lower alkyl alcohol ester.

Examples of polyhydric alcohols that can be used as raw materials for the polyhydric alcohol fatty acid ester (C) include glycerin, trimethylolpropane, erythritol, pentaerythritol, sorbitan, diglycerin, xylitol, triglycerin, sorbitol, dipentaerythritol, inositol, and tetraglycerin, and among these, glycerin, diglycerin, sorbitan, and sorbitol are preferred.

The fatty acid used as the raw material for the polyhydric alcohol fatty acid ester (C) preferably has 10 or more carbon atoms, more preferably 12 or more, from the viewpoint of imparting appropriate bleeding properties. The number of carbon atoms is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. Examples of fatty acids having 8 to 22 carbon atoms include saturated fatty acids such as caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, 12-hydroxystearic acid, arachidic acid, and behenic acid, and unsaturated fatty acids such as decenoic acid, undecenoic acid, dodecenoic acid, tetradecenoic acid, oleic acid, erucic acid, linoleic acid, linolenic acid, and ricinoleic acid. Among these, lauric acid, myristic acid, palmitic acid, and stearic acid are preferred from the viewpoint of antistatic properties and bleeding properties, and palmitic acid and stearic acid are particularly preferred.

Among the polyhydric alcohol fatty acid esters (C), monoglycerin fatty acid esters, diglycerin fatty acid esters, and polyoxyalkylene sorbitan fatty acid esters are preferred from the viewpoint of reducing VOCs.

Monoglycerin fatty acid esters are ester compounds obtained by known methods such as an esterification reaction between monoglycerin and a fatty acid, or an ester exchange reaction between monoglycerin and a fatty acid lower alkyl alcohol ester, and are preferably mono-fatty acid ester compounds of monoglycerin obtained from monoglycerin and a fatty acid having 8 to 22 carbon atoms, but di-fatty acid esters and tri-fatty acid esters may also be present. These may be distilled or used as is.

Diglycerol fatty acid esters are ester compounds obtained by known methods such as the esterification reaction between diglycerol and a fatty acid, or the transesterification reaction between diglycerol and a fatty acid lower alkyl alcohol ester, and are preferably mono-fatty acid ester compounds of diglycerol obtained from diglycerol and a fatty acid having 8 to 22 carbon atoms, but di-fatty acid esters and tri-fatty acid esters may also be present. These may be distilled or used as is.

The raw material diglycerin preferably contains 90% or more by mass of diglycerin, which is condensed by 2 moles of glycerin, but polyglycerin, which is condensed by 3 or 4 moles, may also be present. The fatty acid having 8 to 22 carbon atoms can be the same as that used for monoglycerin fatty acid ester.

Polyoxyalkylene sorbitan fatty acid esters can be obtained, for example, by adding an alkylene oxide to a sorbitan fatty acid ester, which is a partial ester of sorbitol or sorbitan with a fatty acid, but are not particularly limited thereto, and may be a reaction product obtained by esterifying a fatty acid with an alkylene oxide added to sorbitol or sorbitan.

In the polypropylene resin composition for automotive interior materials of the present invention, the amount of polyhydric alcohol fatty acid ester (C) is 0 to 2.0 parts by mass per 100 parts by mass of polypropylene resin (A), but from the viewpoint of antistatic properties and anti-fogging properties, it can be preferably blended in a ratio of 0.01 to 1.0 part by mass, and more preferably 0.1 to 0.4 part by mass.

The total amount of the components (B) and (C) contained in the polypropylene resin composition for automotive interior materials of the present invention is preferably in the range of 0.01 to 2.0 parts by mass per 100 parts by mass of the polypropylene resin, from the viewpoint of imparting an excellent antistatic effect to the polypropylene resin composition. The preferred range of the content of the surfactant composition is 0.1 to 0.5 parts by mass. By keeping it within this range, the surface resistivity value (Log Ω/□) is 13 or less, and fogging and an increase in VOCs caused by the inclusion of the surfactant can be further reduced, which is preferable.

The mass ratio of the (B) component to the (C) component is preferably (B)/(C)=100/0 to 1/99, but from the viewpoint of imparting antistatic properties, it is more preferably 80/20 to 51/49, and even more preferably 80/20 to 70/30. From the viewpoint of VOC, it is preferably 5/95 to 49/51, and even more preferably 5/95 to 30/70.

The polypropylene resin composition for automotive interior materials of the present invention is preferably substantially free of alkyldiethanolamine and/or fatty acid ester of alkyldiethanolamine. By being substantially free of these antistatic agents that have been widely used in the past, fogging and the generation of aldehydes can be significantly suppressed. Here, "substantially free" means that the polypropylene resin composition contains 10 ppm or less, preferably 1 ppm or less, and more preferably 0 ppm.

The polypropylene resin composition for automobile interior materials of the present invention can be blended with an inorganic filler to reinforce and increase the volume of the polypropylene resin composition. The inorganic filler is not particularly limited, but examples thereof include talc, calcium carbonate, barium sulfate, aluminum hydroxide, gypsum, dawsonite, simgon, radiolite, celite, novacite, asbestos, alumina, attapulgite, kaolin gray, volcanic ash, silica, wollastonite, diatomaceous earth, magnesium oxide, magnesium carbonate, feldspar powder, biotite, and magnesium silicate. Among these, the use of talc is preferred. These inorganic fillers may be used alone or in combination of two or more types.

Various rubber components can be blended into the polypropylene resin composition of the present invention in order to impart flexibility, impact resistance, and the like to the composition. The rubber components are not particularly limited, but examples include ethylene-α-olefin copolymer rubber, ethylene-α-olefin-non-conjugated diene copolymer rubber, natural rubber, isoprene rubber, polybutadiene rubber, isobutylene-isoprene copolymer rubber, acrylonitrile-butadiene copolymer rubber, styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, silicone rubber, acrylic rubber, chloroprene rubber, and hydrogenated versions of the above rubbers. Among these, the use of ethylene-α-olefin copolymer rubber and ethylene-α-olefin-non-conjugated diene copolymer rubber (hereinafter, the term "ethylene-based copolymer rubber" refers to both) is preferred. The above rubbers can be used alone or in combination of two or more.

The following describes ethylene-based copolymer rubbers that are preferably used as rubber components. Examples of α-olefins that are copolymerized with ethylene, preferably α-olefins having 3 to 10 carbon atoms, include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, and 1-decene. Two or more of these α-olefins can be used in combination. From the viewpoint of impact resistance, the ethylene component content of the ethylene-based copolymer rubber is 60 to 90 mol%, preferably 70 to 85 mol%.

Non-conjugated dienes include dicyclopentadiene, 1,4-hexadiene, 1,9-decadiene, cyclooctadiene, norbornadiene, methylenenorbornene, ethylidenenorbornene, and 7-methyl-1,6-octadiene.

The iodine value of the ethylene-α-olefin-non-conjugated diene copolymer is preferably 5 to 50, more preferably 10 to 45. The Mooney viscosity (ML ₁₊₄ , 100° C.) of the ethylene copolymer rubber is 10 to 100, preferably 20 to 60, from the viewpoints of dispersibility with polypropylene resin and impact resistance.

Ethylene-based copolymer rubber can be obtained by known polymerization methods, for example, by copolymerization in the presence of vanadium-based, titanium-based, or metallocene-based catalysts.

In addition, in each process from polypropylene resin to the production of molded articles for automobile interior parts, high molecular weight polymers such as poly4-methyl-1-pentene, polystyrene, polybutadiene, styrene graft polymers of polyisoprene, copolymer elastomers obtained by hydrogenating these, polyesters, polyamides, polycarbonates, etc. may be added depending on the purpose of use within a range that does not significantly impair the effects of the present invention. The blending amount of these high molecular weight polymers is usually up to 5 mass%, preferably up to 3 mass%.

In addition to the polypropylene resin, other polymers or elastomers, antistatic agents, and inorganic fillers, additives such as stabilizers against heat, oxygen, and light, weathering agents, crystal nucleating agents, lubricants, flame retardants, and plasticizers that are widely used in the fields of synthetic resins and synthetic rubbers depending on the intended use may be added to the polypropylene resin composition of the present invention, as long as the effects of the present invention are not significantly impaired. In the present invention, pigments may be further added to the polypropylene resin to which these stabilizers or various additives have been added.

Examples of stabilizers against heat and oxygen include phenol-based antioxidants, phosphorus-based antioxidants, and sulfur-based antioxidants. Examples of weathering agents to prevent deterioration due to light include amine-based, triazole-based, benzophenone-based, benzoate-based, nickel-based, and salicylic acid-based compounds. Examples of crystal nucleating agents include sorbitol-based, phosphorus-based, rosin-based, organic phosphate metal salts, and carboxylate metal salts. Examples of lubricants include fatty acid amides, higher alcohols, and polyethylene wax. Examples of flame retardants include phosphate-based, melamine-based, phosphorus-based, halogen-based, and non-halogen-based compounds. Examples of plasticizers include phthalate-based, fatty acid-based, adipate-based, trimellitate-based, epoxy-based, and polyester-based compounds.

Pigments include inorganic pigments and organic pigments. Inorganic pigments are inorganic in the color-producing portion, and include those composed of single elements as components, as well as oxides, sulfides, and sulfates of Zn, Pb, Ti, Sb, Cd, Fe, As, Mg, Al, Co, Cr, etc. Organic pigments are organic compounds in the color-producing portion, and include azo pigments, polyazo pigments, atine pigments, copper phthalocyanine pigments, dioxane pigments, and quinacridone pigments. Dispersing aids (such as fatty acid metal salts, naphthenic acid metal salts, surfactants, silicone oil, and lecithin) may be used to improve the dispersibility of pigments in polypropylene.

When the polypropylene resin composition for automobile interior materials of the present invention is used to produce a molded product, it can be produced by blending the main component polypropylene resin with the components (B) to (C) of the present invention by a normal method, and other polymers, inorganic fillers, pigments, and other additives may also be blended. For example, the components (B) to (C) of the present invention, and if necessary, inorganic fillers, pigments, and other additives are blended with a powdered or pelletized polypropylene resin and other polymers, and the mixture is mixed in a Henschel mixer, a tumbler mixer, or the like, and then melt-kneaded in a single-screw or twin-screw kneading extruder to form pellets. The pellets thus obtained are processed into a molded product by an injection molding machine. If the MFR of the polypropylene resin composition is less than 5 g/10 min, the moldability in injection molding is poor and the composition is not suitable for use as an automobile interior part. If the MFR exceeds 150 g/10 min, the composition is poor in impact resistance and is not suitable for use as an automobile interior part.

The molded article for automobile interior parts of the present invention is a molded article obtained by molding the polypropylene-based resin composition of the present invention by a known molding method, and examples of such molded articles include injection molded articles, press molded articles, vacuum molded articles, vacuum press molded articles, compressed air molded articles, foam molded articles, and extrusion molded articles.

The molded article for automobile interior parts of the present invention is preferably an injection molded article. Examples of injection molding methods include general injection molding, injection foam molding, supercritical injection foam molding, ultra-high speed injection molding, injection compression molding, injection press molding, gas-assisted injection molding, sandwich molding, sandwich foam molding, and insert-outsert molding.

Applications of the molded article for automotive interior parts of the present invention include, for example, door trims, pillars, instrument panels, consoles, rocker panels, arm rests, door panels, spare tire covers, etc.

The molded body for automobile interior parts of the present invention can be produced by injection molding the polypropylene resin composition. The molding temperature is generally 150 to 350°C, preferably 170 to 250°C. If the molding temperature exceeds 350°C, it will cause deterioration of the resin composition and molding defects, and if it is lower than 150°C, poor appearance and molding defects will occur. It is preferable to carry out the molding temperature in the range of 10 to 60°C. If the mold temperature exceeds 60°C, the molded body will have an excellent surface finish and a molded body with excellent rigidity will be obtained, but the molding cycle will be long and productivity will decrease. Conversely, if the mold temperature is set to a temperature lower than 10°C, warping and shrinkage will become significant, making it difficult to obtain a satisfactory molded body, and condensation will easily occur on the mold, causing mold corrosion to progress. It is also not suitable from the viewpoint of energy costs related to cooling.

The present invention will now be described with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, the amounts of ingredients are expressed in parts by weight.

[Synthesis Example 1: Synthesis of alcohol alkylene oxide adduct]
1000 g of stearyl alcohol and 1 g of 96% potassium hydroxide were charged into a stainless steel high-pressure reactor equipped with a thermometer, a stirrer, a pressure gauge, and a nitrogen inlet tube, the inside of the reactor was replaced with nitrogen, and the reactor was heated under a nitrogen atmosphere to 120° C. Then, 173 g of ethylene oxide (hereinafter referred to as EO) was introduced into the reactor over 5 hours while maintaining the temperature at 150° C. under a safe pressure, and the temperature was maintained for one hour to complete the alkylene oxide addition reaction, thereby obtaining a stearyl alcohol alkylene oxide adduct (average number of moles of EO added: 1 mole).

[Production Example 1: Synthesis of phosphoric acid ester compound]
In a reaction vessel equipped with a thermometer, a stirrer, a nitrogen inlet tube, a condenser, and a water sample tube, 1002 g of the methanol alkylene oxide adduct obtained in Synthesis Example 1 was charged and heated to 40° C. Next, 185 g of 89% phosphoric acid (manufactured by Rasa Kogyo Co., Ltd.) was added dropwise over 4 hours, and after the completion of the dropwise addition, the mixture was aged at the same temperature for 2 hours. Thereafter, the mixture was heated to 95° C. and aged for 4 hours while introducing nitrogen from the bottom at 5 m ³ /hr. After confirming that 90% or more of the theoretical amount of reaction water had been distilled into the water sample tube, the reaction was terminated and phosphate ester compound (1) was obtained.

[Production Examples 2 to 8: Synthesis of Phosphate Compounds (2) to (8)]
As shown in Table 1, phosphoric acid ester compounds (2) to (8) were produced in the same manner as in Production Example 1, except that the average molar number of alkylene oxide added in the alcohol alkylene oxide adduct and the type of alcohol were changed.

(Manufacturing of injection molded bodies)
[Examples 1 to 10 and Comparative Examples 1 to 8]
Using Novatec MA1B manufactured by Japan Polypropylene Corporation as polypropylene resin (A), the types and amounts of components (B) to (C) shown in Tables 3 and 4 below were blended in a twin-screw extruder (TEM26SS manufactured by Toshiba Machine Co., Ltd.) and melt-kneaded (screw rotation speed: 250 rpm, cylinder temperature: 200° C.). The extrudate was cooled and solidified with cold water and cut to obtain resin component compound pellets.
The prepared compound was molded at a molding temperature of 190° C. in a hybrid injection molding machine FNX140 manufactured by Nissei Plastic Industrial Co., Ltd. into flat test plates measuring 150 mm×150 mm×3 mm.

Measurement and evaluation of each evaluation item was performed using the following methods. The results are shown in Tables 3 and 4.

(1) Evaluation of antistatic properties The prepared test plate was left for 14 days under conditions of 23°C and 50% humidity, and then the surface resistivity was measured using a Hiresta UP MCP-HT450 manufactured by Mitsubishi Chemical Analytech Co., Ltd. Here, the effective surface resistivity for preventing adhesion of dirt and dust to a molded product was determined to be 13.0 (log Ω/□) or less based on past knowledge.

(2) Evaluation of fogging prevention Two pieces of 25 mm x 100 mm x 3 mmt were cut out from the test plate to be used as samples for evaluating fogging properties. The evaluation of fogging properties was performed using a Thomas Scientific fogging tester (constant temperature oil bath) with the glass container heated to 100°C for 20 hours. After the heat treatment was completed, the glass plate with the fogging attached was taken out and left for 1 hour under conditions of 23°C and 50% humidity, and then the total light transmittance of the glass plate was measured using a haze meter HM-150 L2 type manufactured by Murakami Color Technology Research Co., Ltd. to evaluate the fogging prevention properties. Here, the fogging property that does not interfere with visibility when riding in a car was defined as less than 5%.

(3) Evaluation of Bleeding Property A test piece was placed in an oven set at 40° C. for 200 hours, and after being taken out, the appearance was visually observed and evaluated according to the following criteria.
◯: Bleeding was not observed with the naked eye. Δ: Bleeding was observed with the naked eye. ×: Bleeding was easily observed with the naked eye, and the composition could not be used for practical purposes.

(4) Acetaldehyde and formaldehyde emission amounts The acetaldehyde emission amounts were measured by the following method using test pieces cut to a size of 80 mm x 100 mm from the flat plate molded article obtained by the above-mentioned [Production of injection molded article].
(i) The test piece was sealed in a sampling bag having a volume of 10 L, and the bag was filled with pure nitrogen gas. After that, the pure nitrogen gas was removed, and the gas in the sampling bag was replaced with nitrogen gas. This operation was repeated twice.
(ii) The sampling bag was filled with 4 L of pure nitrogen gas and the tap of the sampling bag was closed. The sampling bag was placed in an oven, a Teflon (registered trademark) tube for sampling was attached to the tip of the tap and extended to the outside of the oven, and in this state, heat treatment was performed at 65°C for 2 hours.

(iii) Collection and measurement of acetaldehyde and formaldehyde After collecting 1 L of the sample gas prepared in (ii) above in a simulated adsorption tube under a heated state of 65° C., the remaining sample gas was collected in its entirety into a 2,4-dinitrophenylhydrazine (abbreviation: DNPH) cartridge at a collection rate of 0.4 L/min. The cartridge after collection was subjected to an elution treatment with acetonitrile, and the obtained eluate was used to measure the components eluted from the cartridge using a high performance liquid chromatograph (HPLC; manufactured by Waters, model: Ultra Performance Liquid Chromatography Aquiy).

The amount of acetaldehyde and formaldehyde emitted (amount of acetaldehyde and formaldehyde emitted from one test piece of a specified size, unit: μg/test piece) was calculated using the calibration curve of the standard substance of the component. Here, the amount of aldehyde emitted that is suitable for automotive interior materials is set to 0.150 μg/test piece or less.

As shown in Table 3, all of the polypropylene resin compositions of Examples 1 to 10 were excellent in antistatic properties and anti-bleeding properties. In addition, fogging and generation of aldehydes were significantly suppressed.
In contrast, as shown in Table 4, in the polypropylene resin compositions of Comparative Examples 1 to 8, fogging and generation of aldehydes were observed.

Claims (7)

For 100 parts by mass of polypropylene resin (A),
0.01 to 2.0 parts by mass of a phosphoric acid ester compound (B) represented by the following chemical formula (1) (excluding those having 4 or more moles of ethylene oxide added):

(In the formula, R is an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, or an aryl group which may have a substituent; AO is an oxyalkylene group having 2 to 4 carbon atoms; n is the average number of moles of alkylene oxide added and is a number from 1 to 10; m is 1 or 2 ; and M is a hydrogen atom, an alkali metal, a Group 2 metal, an ammonium group, or an organic ammonium group.)
A polypropylene resin composition for automobile interior materials comprising: For 100 parts by mass of polypropylene resin (A),
0.01 to 2.0 parts by mass of a phosphoric acid ester compound (B) represented by the following chemical formula (1):

(In the formula, R is an alkyl group having 1 to 24 carbon atoms, an alkenyl group having 2 to 24 carbon atoms, or an aryl group which may have a substituent; AO is an oxyalkylene group having 2 to 4 carbon atoms; n is the average number of moles of alkylene oxide added and is a number of 1 to 2 ; m is 1 or 2 ; and M is a hydrogen atom, an alkali metal, a Group 2 metal, an ammonium group, or an organic ammonium group.)
A polypropylene resin composition for automobile interior materials comprising: For 100 parts by mass of polypropylene resin (A),
Further, 0.01 to 2.0 parts by mass of a polyhydric alcohol fatty acid ester (C) is blended.
The polypropylene resin composition for automobile interior materials according to claim 1 or 2 . 4. The polypropylene resin composition for automobile interior materials according to claim 3 , comprising 0.01 to 2.0 parts by mass in total of the components (B) and (C). The polypropylene resin composition for automobile interior materials according to any one of claims 1 to 4 , wherein a mass ratio of the component (B) to the total of the component (C) is (B)/(C)=100/0 to 1/99. 6. The polypropylene resin composition according to claim 1 , which is substantially free of alkyldiethanolamine and/or fatty acid ester of alkyldiethanolamine. A molded article for automobile interior parts, obtained by molding the polypropylene resin composition according to any one of claims 1 to 6 .