JP3609917B2 - Vinyl chloride resin composition - Google Patents

Description

【００４５】
こうして得られたペレットを、シリンダー径４０ｍｍの一軸押出機により下記条件にて押出発泡成形した。なお、比較例８においては所定量のトリクロロフルオロメタンを高圧ポンプでシリンダーのベント孔から圧入した。成形品の特性を表２に示す。

【００４６】
【表１】

【００４７】
注
ＭＭＡ ：メチルメタクリレート
ＭＡ ：メチルアクリレート
ＥＡ ：エチルアクリレート
ｎ−ＢＡ ：ｎ−ブチルアクリレート
２−ＥＨＡ：２−エチルヘキシルアクリレート
ＳＴ ：スチレン
【００４８】
【表２】

【００４９】
注
＊１ ＺＥＳＴ７００Ｌ、新第一塩ビ（株）製、塩化ビニル樹脂、平均重合度６８０
＊２ 酸化チタン粒付着木粉、ミサワテクノ（株）製、Ｅ６０−Ｔ５−３、酸化チタン含有量５重量％、平均粒径６０μｍ、含水率５％
＊３ セルユント、（株）シマダ商会製、木粉、平均粒径８０μｍ、水分５重量％
＊４ ＡＣＰＥ６Ａ、アライドケミカル社製
＊５ 三塩基性硫酸鉛／ステアリン酸鉛複合熱安定剤
＊６ 炭酸カルシウムＣＣＲ、白石カルシウム（株）製、平均粒径０．０８μｍ
＊７ カーボンブラック（ＴＰＨ００１２、東洋インキ製造株式会社製）／縮合アゾレッド（ＴＸＨ４３６０、同社製）／ビスアゾイエロー（ＴＸＨ２１１０、同社製）複合顔料
【００５０】
本発明の要件を備えた組成物を用いて成形した実施例１〜６では、発泡セル状態および表面性状が良好で十分な発泡倍率を有する成形品が得られた。殊に滑剤としてステアリン酸鉛およびポリエチレンワックスを併用すると発泡倍率と抗張力が一層優れた成形品が得られる（実施例１、２および５）。
しかし、メチルメタクリレート系共重合体のガラス転移点が８５℃を越える共重合体Ｄを用いた比較例１では破壊されて粗くなったセルが多くて若干鮫肌状の表面を有する発泡体が得られ、逆に、ガラス転移点が５０℃未満の共重合体ＥまたはＦを用いた比較例２および比較例３では発泡セル状態は良好であったが発泡体の表面は鮫肌状で不満足の結果となった。
メチルメタクリレート系共重合体の比粘度が規定より小さい共重合体ＥまたはＧを用いた比較例２および比較例４も鮫肌状の発泡体表面を与えかつ、発泡倍率が低い。逆に、比粘度が規定より大きい共重合体Ｈを用いた比較例５は発泡体のセル状態が粗く、表面がやや粗く、発泡倍率も劣る結果を与えた。
【００５１】
メチルメタクリレート系共重合体の配合部数が規定より小さい比較例６や規定より多い比較例７では、共にセル状態及び表面の粗い発泡体が得られた。
発泡剤として低沸点の有機化合物を用いた比較例８では発泡セルは破壊されて粗くなったものが多く、成形品表面も鮫肌状に荒れた。
（Ｅ）成分の可塑剤を欠く配合は表面が鮫肌状に荒れた成形品を与えた（比較例９）。また、可塑剤の欠如を滑剤の増量で挽回することはできない（比較例１０）。可塑剤が多過ぎるとセルの保持が悪くなってセル状態が悪化し発泡倍率も低くなり、抗張力が低下する（比較例１１）。
【００５２】
【発明の効果】
本発明組成物を用いることにより、均一微細な発泡セル構造と平滑な表皮とを有し、しかも木質感に富んで十分な機械的強度を持つ、建材や家具材に適する塩化ビニル系樹脂成形品が得られる。
【図面の簡単な説明】
【図１】本発明で使用するメチルメタクリレート系共重合体の比粘度ｙとＧＰＣ法による標準ポリスチレン換算重量平均分子量ｘとの関係を表わすグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vinyl chloride resin composition containing a large amount of wood flour.
This wood powder-containing vinyl chloride resin composition has a uniform and fine foam cell structure and a smooth skin, is rich in wood texture, and can provide a molded product suitable for building materials and furniture materials.
[0002]
[Prior art]
Since wood can be repeatedly produced by photosynthesis, it is reviewed as a rich and promising resource different from petroleum resins. There is an attempt to nurture forests with fast-growing tree species and reduce the increased carbon dioxide concentration in the atmosphere to restore a healthy global environment, while at the same time systematically cutting and using wood as a resource for human life It is happening. Under such circumstances, we developed a vinyl chloride resin composition that is frequently used in building materials by blending wood powder with vinyl chloride resin, which is a general-purpose resin that has large mechanical strength and is easy to mold. If possible, a harmonious way of using earth resources will be cultivated.
Conventionally, for the purpose of revealing the appearance and feel similar to wood, it is often performed by blending wood powder with vinyl chloride resin. However, a vinyl chloride resin composition containing a considerable amount of wood powder has problems that mechanical strength such as tensile strength is greatly reduced and a natural wood texture has not been realized yet.
[0003]
In order to clarify the grain and improve the ease of processing, a vinyl chloride resin composition in which a urea resin is added in addition to wood flour has been proposed (Japanese Patent Laid-Open Nos. 60-42007 and 60). -73807, JP-A-60-73808). In addition to wood flour, vinyl chloride resin compositions to which inorganic fillers such as mica and polyethylene, ethylene-vinyl acetate copolymer or ABS resin are added have a low coefficient of linear expansion, impact resistance and moldability. (Japanese Unexamined Patent Publication Nos. 60-192746 and 60-192747). However, even with these, the wood powder is not uniformly mixed, and the wood texture of the molded product is insufficient.
Although the uniform dispersion of the wood powder is greatly improved by blending the wood powder to which the inorganic powder or the plastic powder is adhered at the time of plastic processing (JP-A-5-177610, JP-A-5-261708), A resin molded product rich in wood texture has not yet been obtained only by blending such wood powder into a vinyl chloride resin.
[0004]
[Problems to be solved by the invention]
In view of the above situation, an object of the present invention is to have a uniform and fine foam cell structure and a smooth skin, and to maintain the good mechanical strength inherent to the vinyl chloride resin molded product, and to make the wood texture. The object is to provide a vinyl chloride resin composition that can give a molded product that is rich and reaches building materials such as window frames and furniture materials.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present inventors blended a vinyl chloride-based resin with a wood powder and a methyl methacrylate-based copolymer having a specific glass transition point as a processing aid, thereby foam-molding the resin. The inventors have found that the object is achieved, and have completed the present invention based on this finding.
That is, the present invention comprises (A) 100 parts by weight of a vinyl chloride resin, (B) 60% by weight or more of a methyl methacrylate unit, the glass transition point of the copolymer is 50 to 85 ° C., and the specific viscosity is 1 7 to 30 parts by weight of a methyl methacrylate copolymer having a molecular weight of 5 to 4.0, (C) 0.1 to 3.0 parts by weight of a pyrolytic foaming agent, and (D) a wood powder having an average particle size of 50 to 500 μm. There is provided a vinyl chloride resin composition comprising 20 to 150 parts by weight and (E) 1 to 20 parts by weight of a plasticizer.
In addition to the components (A), (B), (C), (D) and (E), the vinyl chloride resin composition further comprises (F) 0.5 to 10 parts by weight of metal soap and ( G) It is preferable to contain 0.1-5.0 weight part of polyethylene waxes.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The vinyl chloride resin used as the component (A) in the composition of the present invention includes a vinyl chloride homopolymer and a copolymer containing 50% by weight or more, preferably 70% by weight or more of vinyl chloride units. Including. Examples of the comonomer in the case of the vinyl chloride copolymer include olefins such as ethylene and propylene; halogenated olefins such as allyl chloride, vinylidene chloride, vinyl fluoride, and ethylene trifluoride chloride; vinyl acetate, Carboxylic acid vinyl esters such as vinyl propionate; Vinyl ethers such as isobutyl vinyl ether and cetyl vinyl ether; Allyl ethers such as allyl-3-chloro-2-oxypropyl ether and allyl glycidyl ether; Acrylic acid, maleic acid, itaconic acid Unsaturated carboxylic acids such as 2-hydroxyethyl acrylate, methyl methacrylate, monomethyl maleate, diethyl maleate, maleic anhydride, esters thereof or anhydrides thereof; unsaturated compounds such as acrylonitrile, methacrylonitrile, etc. Nitriles: Acrylamides such as acrylamide, N-methylolacrylamide, acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropyltrimethylammonium chloride; allylamines such as allylamine benzoate and diallyldimethylammonium chloride and derivatives thereof Can be mentioned. The monomers exemplified above are only a part of the copolymerizable monomers, and are exemplified in pages 75 to 104 of “Polyvinyl Chloride” Nikkan Kogyo Shimbun (1988) edited by the Kinki Chemical Association Vinyl Division. Various monomers can be used. In addition, monomers such as ethylene-vinyl acetate copolymer, ethylene-methyl methacrylate copolymer, ethylene-ethyl acrylate copolymer, chlorinated polyethylene, and the above-mentioned copolymerizable monomers with vinyl chloride or vinyl chloride. Also included are resins such as those obtained by graft polymerization.
[0007]
These vinyl chloride resins may be produced by any conventionally known production method such as suspension polymerization, emulsion polymerization, solution polymerization, and bulk polymerization. The average degree of polymerization of the vinyl chloride resin is preferably from 400 to 1,500, more preferably from 600 to 1,100 as measured by JIS K 6721. If the average degree of polymerization of the vinyl chloride resin is less than 400, the expansion ratio tends to be difficult to increase. Conversely, if the average polymerization degree is greater than 1,500, many foamed cells may be mixed.
[0008]
In the present invention, as the component (B), a methyl methacrylate system containing a methyl methacrylate unit of 60% by weight or more, a glass transition point of the copolymer of 50 to 85 ° C., and a specific viscosity of 1.5 to 4.0. A copolymer is used.
Since the glass transition point of the methyl methacrylate homopolymer is 105 ° C., a homopolymer having a glass transition point sufficiently lower than that of the methyl methacrylate comonomer in order to obtain the copolymer of component (B). It is necessary to select a monomer that gives Examples of such monomers include methyl acrylate (homopolymer glass transition point 8 ° C.), ethyl acrylate (-22 ° C.), n-propyl acrylate (-52 ° C.), n-butyl acrylate (same − 54 ° C), isobutyl acrylate (-24 ° C), n-octyl acrylate (-65 ° C), 2-ethylhexyl acrylate (-85 ° C), n-lauryl acrylate (15 ° C), n-tetradecyl acrylate (20 ° C), methoxyethyl acrylate (-85 ° C), ethoxyethyl acrylate (-50 ° C), cyclohexyl acrylate (15 ° C), benzyl acrylate (6 ° C); n-amyl methacrylate; (10 ° C), n-octyl methacrylate (-20 ° C), n-decyl methacrylate Rate (at -65 ° C.), n- lauryl methacrylate (same -65 ° C.), methacrylates such as n- cetyl methacrylate (same 15 ° C.); butadiene, and the like dienes such as isoprene. These (meth) acrylates may be used alone or in combination of two or more. In particular, n-butyl acrylate is preferable.
[0009]
The copolymer of component (B) contains methyl methacrylate monomer units in an amount of 60% by weight or more and has a glass transition point of 50 to 85 ° C. A monomer that can be copolymerized with A may be contained as a third monomer unit. Examples of such copolymerizable monomers include aromatic vinyl compounds such as styrene, vinyl toluene and α-methyl styrene; unsaturated nitriles such as (meth) acrylonitrile and vinylidene cyanide; 2-hydroxyethyl fuma Examples thereof include rate, hydroxybutyl vinyl ether, monobutyl maleate, glycidyl methacrylate, and butoxyethyl methacrylate.
[0010]
The particle structure of the methyl methacrylate copolymer as the component (B) may be a polymer composition obtained by a one-step polymerization reaction, and the inside of the particles may be substantially uniform, or for each fault as in the so-called core-shell structure. Different polymer compositions may be used.
When the particle structure of the (B) component methyl methacrylate copolymer is a core-shell particle, the weight ratio of the core to the shell is preferably 1/1 to 15/1, and the glass transition point of the core and the shell The difference is preferably 50 ° C. or less.
The glass transition point of the (B) component methyl methacrylate copolymer is required to be 50 to 85 ° C, and preferably 60 to 83 ° C. When the glass transition point of component (B) is less than 50 ° C., the powder tends to stick (block) during storage in a warehouse in the summer, and the glass transition point of component (B) is higher than 85 ° C. The molded product tends to cause foaming failure. In the present invention, the glass transition point is measured with a differential thermal analyzer.
[0011]
The methyl methacrylate copolymer used as the component (B) needs to have a specific viscosity of 1.5 to 4.0 at 25 ° C. in 100 ml of a chloroform solution in which 0.2 gr is dissolved. A range of 3.7 is preferred. When the value of the specific viscosity is less than 1.5, the surface of the molded product is rough and the expansion ratio does not increase. On the other hand, if the value of the specific viscosity exceeds 4.0, it takes time for uniform melting. For adjusting the specific viscosity, a general method such as selection of a polymerization reaction temperature or use of a chain transfer agent such as t-dodecyl mercaptan or carbon tetrachloride can be employed.
[0012]
The specific viscosity is an index of the molecular weight of the (B) component methyl methacrylate copolymer. That is, the above specific viscosity range of 1.5 to 4.0 was measured by high performance liquid chromatography using a mixed gel column under fixed conditions using tetrahydrofuran as an eluent, and calculated in terms of standard polystyrene. The average molecular weight Mw corresponds to about 3,700,000 to about 10,270,000.
The relationship between the specific viscosity of the eight types of methyl methacrylate copolymers A to H prepared in Examples below and the weight average molecular weight in terms of standard polystyrene by the GPC method is shown in FIG. The average molecular weight x is the following formula
y = 3.97 × 10^-7x + 0.02
[0013]
It is represented by
The (B) component methyl methacrylate copolymer improves the melt viscosity characteristics of the vinyl chloride resin, uniformly disperses the wood flour in the vinyl chloride resin, and maintains the film strength of the foamed cells and is not easily destroyed. Have the effect of
In order to obtain a molded article with a high degree of foaming using a vinyl chloride resin composition containing a relatively large amount of wood flour as in the present invention, it has a specific composition and a specific high specific viscosity as described above. It is important to add a methyl methacrylate copolymer and to add a specific amount of the component (E) (plasticizer) in order to improve the melt fluidity during the molding process.
[0014]
The blending amount of the component (B) in the present invention is required to be 7 to 30 parts by weight, preferably 10 to 20 parts by weight, per 100 parts by weight of the vinyl chloride resin of the component (A).
When the blending amount of the component (B) is less than 7 parts by weight, the retention strength of the film strength at the time of foaming becomes weak, and the foamed cells are easily destroyed. On the other hand, when the blending amount exceeds 30 parts by weight, the melt viscosity becomes high, the heat generation becomes large, the resin is likely to be thermally deteriorated, and the size of the foamed cell tends to be non-uniform.
[0015]
As the pyrolyzable foaming agent which is the component (C) of the composition of the present invention, a pyrolyzable organic foaming agent and / or a pyrolyzable inorganic foaming agent is used. Examples of the former include nitroso compounds such as N, N′-dinitrosopentamethylenetetramine and N, N′-dimethyl-N, N′-dinitrosotephthalamide; azos such as azodicarbonamide and azobisisoptyronitrile. Compounds; sulfonyl hydrazides such as benzenesulfonyl hydrazide, p, p′-oxybis (benzenesulfonyl hydrazide), toluenesulfonyl hydrazide and the like. Examples of the latter include sodium bicarbonate, ammonium bicarbonate, ammonium carbonate and the like. In this invention, 1 type (s) or 2 or more types selected from the group of said organic or / and inorganic pyrolytic foaming agent can be used.
[0016]
In the present invention, it is inappropriate to heat and volatilize low boiling point organic compounds such as butane, methyl chloride, trichlorofluoromethane, trifluoromethane, and petroleum ether to use as a blowing agent. This is because the foamed cell becomes rough and the molded product becomes difficult to use with nails or screws, which may not be suitable for building materials.
In the present invention, the amount of the pyrolytic foaming agent of component (C) is required to be 0.1 to 3.0 parts by weight, preferably 0.5 to 100 parts by weight per 100 parts by weight of vinyl chloride resin of component (A). 1.5 parts by weight. When the blending amount of the component (C) is less than 0.1 parts by weight, the inside of the molded product obtained with a low foaming ratio tends to lack the wood texture, and conversely if it exceeds 3.0 parts by weight, the surface of the molded product Tends to be rough and the surface hardness tends to decrease.
[0017]
In the present invention, as component (D), wood powder having an average particle size of 50 to 500 μm is 20 to 150 parts by weight, preferably 25 to 120 parts by weight, more preferably 100 parts by weight of vinyl chloride resin (A). 30 to 100 parts by weight are used. When the blending amount of the wood powder is less than 20 parts by weight, it is difficult to express the wood texture in the molded product, and when it exceeds 150 parts by weight, the molded product becomes brittle. In the present invention, by blending the component (B), even if blended with wood powder in an amount of more than 20 parts by weight, combined with the action of the plasticizer of the component (E), the vinyl chloride resin is familiar. Further, since it can be uniformly dispersed, foam molding has uniform and fine foam cells and a smooth skin, and can express a wood texture strongly. In addition, when the (F) component and the (G) component are combined and blended, the workability is improved and the mechanical strength of the obtained molded product can be improved.
[0018]
The tree species of the wood powder used in the present invention is not particularly limited, and wood such as softwood such as cedar, tsuga and lawan, timber pieces of hardwood, sawdust, sawdust and the like can be used. In order to obtain the component (D) of the present invention from these woods, for example, the wood is preferably made into a relatively rounded wood powder having an average particle size of 500 μm or less by a pulverizer.
The wood flour used in the present invention may be wood flour having hard small particles attached to the surface as disclosed in JP-A-5-177610 and JP-A-5-261708. As the hard small particles, particles having a hardness higher than that of wood flour and an average particle size smaller than that of wood flour are used. Specific examples include metals, metal oxides and metal salts, inorganic compounds, and plastic particles. Preferred small particles are inorganic or metallic particles such as titanium oxide, nickel, calcium carbonate, silica, mica. The mode that hard small particles adhere to the surface of wood flour is hard, such as embedment including entanglement of hard small particles into wood flour, or narrowing binding between multiple entangled hard small particles. Adhesion by pressing external force against the surface of the small particle wood powder may be used, or hard small particles may be adhered to the wood powder with an adhesive. In this case, the above-mentioned wood powder is charged into a ball mill or the like together with 1-50% by weight of hard small particles, and treated under a condition in which dust explosion is prevented such as in a nitrogen atmosphere.
[0019]
The average particle diameter of (D) component used for this invention is 50-500 micrometers, Preferably it is 30-100 micrometers. Here, the average particle diameter refers to a reading of the value of the opening corresponding to 50% by weight of the powder by performing a sieve analysis to obtain a cumulative weight% curve with respect to the opening. When the average particle size of the component (D) is less than 50 μm, the bulk specific gravity becomes small and the mixing operability for preparing the composition is deteriorated.
(D) It is preferable that the water | moisture content in a component is 10 weight% or less, More preferably, it is 5 weight% or less.
[0020]
The plasticizer of the component (E) is combined with the methyl methacrylate copolymer of the component (B), and the wood chloride is contained in the vinyl chloride resin composition even though a relatively large amount of the wood flour is blended. It is important in that it is possible to provide a molded article that is uniformly dispersed and, as a result, has uniform fine foam cells and has a sufficient wood texture. The amount of the plasticizer (E) is 0.1 to 20 parts by weight, preferably 3 to 10 parts by weight per 100 parts by weight of the vinyl chloride resin (A). When the plasticizer (E) is less than 0.1 part by weight, the melt fluidity sufficient to obtain the above-mentioned effect cannot be imparted, and the foam surface tends to be rough like a scaly skin. On the other hand, if it exceeds 20 parts by weight, the retention ability of the foamed cell is lowered, the rigidity of the molded product is lowered, and it is unsuitable for building materials and furniture materials.
[0021]
There is no restriction | limiting in particular as a plasticizer of (E) component, For example, what is conventionally used as a plasticizer in the process of vinyl chloride resin, for example, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, di- (2-ethylhexyl) phthalate , Di-n-octyl phthalate, diisobutyl phthalate, diheptyl phthalate, diphenyl phthalate, diisodecyl phthalate, ditridecyl phthalate, diundecyl phthalate, di (heptyl, nonyl, undecyl) phthalate, benzyl phthalate, butyl benzyl phthalate, dinonyl phthalate, Phthalic acid derivatives such as dicyclohexyl phthalate; isophthalic acid derivatives such as dimethyl isophthalate, di- (2-ethylhexyl) isophthalate, diisooctyl isophthalate; di- (2- Adipic acid derivatives such as di-n-butyladipate, di (2-ethylhexyl) adipate, diisodecyladipate, diisononyladipate; dithionyl) tetrahydrophthalate, di-n-octyltetrahydrophthalate, diisodecyltetrahydrophthalate and the like; Azelaic acid derivatives such as-(2-ethylhexyl) azelate, diisooctylazelate, di-n-hexylazelate; sebacic acid derivatives such as di-n-butyl sebacate, di- (2-ethylhexyl) sebacate; -Maleic acid derivatives such as butyl malate, dimethyl malate, diethyl malate, di- (2-ethylhexyl) malate; di-n-butyl fumarate, di- (2-ethylhexyl) fumarate, etc. Fumaric acid derivatives; tri- (2-ethylhexyl) trimellitate, tri-n-octyl trimellitate, triisodecyl trimellitate, triisooctyl trimellitate, tri-n-hexyl trimellitate, triisononyl trimellitate Trimellitic acid derivatives such as tate; pyromellitic acid derivatives such as tetra- (2-ethylhexyl) pyromellitate and tetra-n-octylpyromellitate; triethyl citrate, tri-n-butyl citrate, acetyl triethyl citrate, acetyl Citric acid derivatives such as tri- (2-ethylhexyl) citrate; itaco such as monomethyl itaconate, monobutyl itaconate, dimethyl itaconate, diethyl itaconate, dibutyl itaconate, di- (2-ethylhexyl) itaconate Acid derivatives; oleic acid derivatives such as butyl oleate, glyceryl monooleate, and diethylene glycol monooleate; ricinoleic acid derivatives such as methyl acetyl ricinolate, butyl acetyl ricinolate, glyceryl mono ricinolate, and diethylene glycol mono ricinolate; n-butyl stearate , Stearic acid derivatives such as glycerin monostearate and diethylene glycol distearate; other fatty acid derivatives such as diethylene glycol monolaurate, diethylene glycol dipelargonate, pentaerythritol fatty acid ester; triethyl phosphate, tributyl phosphate, tri- (2-ethylhexyl) Phosphate, tributoxyethyl phosphate, triphenyl phosphate, cresyl dipheny Phosphate derivatives such as phosphate, tricresyl phosphate, trixylenyl phosphate, tris (chloroethyl) phosphate; diethylene glycol dibenzoate, dipropylene glycol dibenzoate, triethylene glycol dibenzoate, triethylene glycol di- (2-ethylbutyrate) ), Triethylene glycol di- (2-ethylhexoate), glycol derivatives such as dibutylmethylene bisthioglycolate; glycerol derivatives such as glycerol monoacetate, glycerol triacetate, glycerol tributyrate; epoxidized soybean oil, epoxyhexa Epoxy derivatives such as diisodecyl hydrophthalate, epoxy triglyceride, epoxidized octyl oleate, and epoxidized decyl oleate So-called primary plasticizers such as polyester plasticizers such as adipic acid polyester, sebacic acid polyester and phthalic polyester; and fatty acid esters of glycols such as chlorinated paraffin and triethylene glycol dicaprylate, butyl epoxy stearate Secondary plasticizers such as rate, phenyl oleate, methyl dihydroabietic acid are exemplified. A plasticizer may be used alone or in combination of two or more. However, when a secondary plasticizer is used, it is preferable to use a primary plasticizer with an equal weight or more.
[0022]
In addition to the above components, the composition of the present invention includes, in addition to heat stabilizers and lubricants used in the processing of ordinary vinyl chloride resins, UV absorbers, impact resistance enhancers, pigments, fillers, and antistatic agents. An agent or the like is appropriately added.
Specific examples of the lubricant include lithium stearate, magnesium stearate, aluminum stearate, calcium stearate, strontium stearate, barium stearate, calcium laurate, barium laurate, barium 2-ethylhexoate, barium ricinoleate, and zinc stearate. , Metal soaps such as zinc naphthenate, cadmium laurate, lead stearate, dibasic lead phthalate; fatty acid esters such as n-butyl stearate, methyl hydroxy stearate, polyhydric alcohol fatty acid ester, ester wax Fatty acids such as stearic acid and hydroxystearic acid; stearamide, oxystearamide, oleylamide, behenamide, methylenebisstearamide, ethylenebis Aroamido, N, N'amide compounds such as distearyl acid amide; tribasic sulfate, basic sulfite lead, and the like inorganic acids lead such as dibasic lead phosphite.
In particular, it is preferable to add 0.5 to 10 parts by weight of the metal soap as component (F) to the composition of the present invention per 100 parts by weight of the vinyl chloride resin because the workability is improved. More preferably. In addition to this, addition of 0.1 to 5 parts by weight of polyethylene wax as component (G) is preferable because it further improves processability and increases the mechanical strength of the molded product, and is preferably 0.3 to 2 parts by weight. It is more preferable to add.
[0023]
In order to prepare the composition of the present invention, usually, the components (A), (B), (D) and (E) except for the pyrolyzable foaming agent (C) are first combined into a Henschel mixer or the like. The mixture is charged into a mixer and heated to 120 to 160 ° C. while mixing, preferably by vigorous stirring. Moisture absorbed by the wood flour is volatilized during the mixing process. When the temperature is reached, the mixture is transferred to a cooling mixer, and when the temperature falls to 110 to 80 ° C., the pyrolytic foaming agent of component (C) is added and then cooled while mixing. Usually, the temperature is lowered to about 50 to 60 ° C. The extracted powdery mixture can be used as a molding compound as it is, but usually, it is then pelletized. A preferable method for producing the pellet includes a method of producing a pellet using a twin-screw extruder at 150 to 170 ° C. while discharging residual moisture in the wood flour from the vent hole.
[0024]
In the above method for preparing the composition of the present invention, the bulk specific gravity is large and the additives such as pigments are uniformly distributed by adding all the components except the foaming agent at the time of initial mixing in a Henschel mixer or the like. A dispersed mixture can be obtained.
Although there is no restriction | limiting in particular as a shaping | molding method for obtaining the vinyl chloride-type resin molded product similar to natural wood using this invention composition, Usually, an extrusion molding method is taken. The conditions for extrusion molding are the same as those for extrusion molding of a general vinyl chloride resin.
[0025]
Thus, the resulting extruded foamed product has fine cells that are uniformly distributed. Usually, the average diameter of the cells is 100 μm or less. Moreover, it is preferable that the expansion ratio of an extrusion foaming molded article is 1.8-2.5. If the expansion ratio is too low, the wood texture is poor, and conversely, if the expansion ratio is too high, the mechanical strength decreases. The form of the extrusion-molded product may be in accordance with the use such as building materials and furniture materials, and generally includes a plate shape, a sheet shape, a prismatic shape, a columnar shape, an irregular shape, and the like.
[0026]
Preferred embodiments of the vinyl chloride resin composition of the present invention described in (1) below are shown in (2) below.
(1) (A) 100 parts by weight of vinyl chloride resin, (B) containing 60% by weight or more of a methyl methacrylate unit, the glass transition point of the copolymer is 50 to 85 ° C., and the specific viscosity is 1.5 to 4.0 to 4.0 parts by weight of methyl methacrylate copolymer, (C) 0.1 to 3.0 parts by weight of pyrolytic foaming agent, and (D) wood powder 20 to 150 with an average particle size of 50 to 500 μm. A vinyl chloride resin composition comprising 1 part by weight and (E) 1 to 20 parts by weight of a plasticizer.
[0027]
(2) The vinyl chloride resin composition according to the above (1), wherein the vinyl chloride resin (A) has an average degree of polymerization of 400 to 1,500.
(3) The vinyl chloride resin composition as described in (1) or (2) above, wherein the methyl methacrylate copolymer (B) has a specific viscosity of 1.8 to 3.7.
(4) The vinyl chloride resin composition according to any one of (1) to (3), wherein the glass transition point of the methyl methacrylate copolymer is 60 to 75 ° C.
(5) The vinyl chloride resin composition according to any one of (1) to (4), wherein the content of the wood flour (D) having an average particle size of 50 to 500 μm is 25 to 120 parts by weight.
[0028]
(6) In addition to the above components (A), (B), (C), (D) and (E), (F) metal soap 0.5 to 100 parts by weight of vinyl chloride resin (A) The vinyl chloride resin composition according to any one of (1) to (5) above, containing 10.0 parts by weight and (G) 0.1 to 5.0 parts by weight of polyethylene wax.
(7) The vinyl chloride resin composition according to (6), wherein the amount of metal soap (F) is 1.5 to 7 parts by weight.
(8) The vinyl chloride resin composition according to the above (6) or (7), wherein the amount of the polyethylene wax (G) is 0.3 to 2 parts by weight.
[0029]
【Example】
Next, although an Example and a comparative example are given and the vinyl chloride resin composition of this invention is demonstrated concretely, this invention is not limited to these Examples. The number of parts and% are based on weight.
Methyl methacrylate copolymers A to H were prepared by the methods described in Production Examples 1 to 8 below. The properties of the copolymer were evaluated by the following methods.
[0030]
Glass transition point
It measured with the differential thermal analyzer (SEIKO SSC / 520 DSC220).
Specific viscosity
The specific viscosity at 25 ° C. of 100 ml of a chloroform solution in which 0.2 gr of the copolymer was dissolved was determined.
[0031]
Weight average molecular weight
The weight average molecular weight Mw was determined by high performance liquid chromatography under the following conditions and converted to standard polystyrene.
High performance liquid chromatography: TOSOH HLC-8020 (manufactured by Tosoh Corporation)
Column: Mix gel TOSOH TSKgel GMH_HR-H (20) x 2 (7.8 mm ID x 30.0 cmL)
Eluent: THF (Wako Pure Chemical Industries, Ltd., GR grade)
Flow rate: 1.0 ml / min
Column temperature: 40 ° C
Injection volume: 150 μl of sample, 0.1 wt% THF solution, 50 μl of standard polystyrene
Detector: differential refractometer (35 ° C)
Standard polystyrene: manufactured by Tosoh Corporation
F2000Mw2.0600 × 10⁷(0.025 wt% THF solution)
F700 6.7700 × 10⁶(0.1 wt% THF solution)
F128 1.0900 × 10⁶(0.1 wt% THF solution)
F20 1.9000 × 10⁵(0.1 wt% THF solution)
F4 3.7900 × 10⁴(0.1 wt% THF solution)
A5000 5.9700 × 10³(0.1 wt% THF solution)
[0032]
Coagulability
Carbon 50g is added to 50g of powder obtained by coagulation, sieve analysis is performed for 30 minutes with a low tap, and the following three grades are evaluated.
A: 50% by weight passage diameter is 150 to 500 μm, and
150 mesh passage <1% by weight
B: 50% by weight passage diameter is 150 to 500 μm, and
150 mesh passage 1-5% by weight
C: 50% by weight passage diameter is 150 to 500 μm, and
150 mesh passage> 5% by weight
[0033]
Solidified powder adhesion
Whether the contents are filled with solidified powder in a cylinder with a diameter of 77 mm and length of 75 mm by natural fall, and then the load is removed over 1 minute. Observe or not. If it breaks down, increase the load in order, check the load that the powder adheres without breaking down, and evaluate according to the following three grades.
A: It does not stick even with a load of 1000 g.
B: It adheres with the load of 500-1000g.
C: It adheres with a load smaller than 500 g.
[0034]
Methyl methacrylate copolymer production example 1
After degassing by putting 150 parts of water in a stainless steel reactor, 85 parts of methyl methacrylate, 15 parts of n-butyl acrylate, 1 part of sodium alkyl sulfate having an alkyl group having 12 to 18 carbon atoms, and potassium persulfate 0.1 The emulsion was subjected to emulsion polymerization at a polymerization temperature of 55 ° C. while stirring, and after confirming a polymerization rate of 91% based on the solid content concentration of a sampled reaction solution, the reaction was terminated to obtain a latex.
The obtained latex was added to a 1% by weight aluminum sulfate aqueous solution at 50 ° C. with stirring, and further heated to 90 ° C. to salt out, coagulate, dehydrated, washed, and dried to obtain a copolymer A. . Table 1 shows the composition, glass transition point, specific viscosity, weight average molecular weight, coagulation property, and adhesiveness of copolymer A.
[0035]
Methyl methacrylate copolymer production example 2
Copolymer B was obtained in the same manner as in methyl methacrylate copolymer production example 1 except that 80 parts of methyl methacrylate and 20 parts of ethyl acrylate instead of 15 parts of n-butyl acrylate were used. Test results such as the composition of copolymer B are also shown in Table 1.
[0036]
Methyl methacrylate copolymer production example 3
Degassing by putting 150 parts of water in a stainless steel container, 0.8 parts of sodium alkyl sulfate having an alkyl group having 12 to 18 carbon atoms, 0.8 parts of lauryl alcohol, 0.2 parts of lauroyl peroxide, methyl methacrylate 60 parts, 30 parts of methyl acrylate and 10 parts of styrene were charged, mixed at room temperature for 30 minutes, homogenized with a homogenizer, and transferred to a stainless steel reactor. The temperature of the reactor was raised and the reaction temperature was maintained at 55 ° C. to carry out the polymerization reaction. After confirming the polymerization rate of 90% based on the solid content concentration of the sampled reaction solution, the reaction was completed to obtain latex. Salting out, washing and drying were carried out in the same manner as in Production Example 1 of methyl methacrylate copolymer to obtain Resin C. Test results such as the composition of Resin C are shown in Table 1.
[0037]
Methyl methacrylate copolymer production example 4
Copolymer D was obtained in the same manner as in methyl methacrylate copolymer production example 1 except that 90 parts of methyl methacrylate and 10 parts of ethyl acrylate instead of 15 parts of n-butyl acrylate were used. The test results such as the composition of the copolymer D are also shown in Table 1.
[0038]
Methyl methacrylate copolymer production example 5
Same as methyl methacrylate copolymer production example 3, except that 65 parts of methyl methacrylate, 35 parts of 2-ethylhexyl acrylate instead of 40 parts in total of methyl acrylate and styrene, and 0.3 part of t-dodecyl mercaptan were added. The copolymer E was obtained. The test results such as the composition of the copolymer E are also shown in Table 1.
[0039]
Methyl methacrylate copolymer production example 6
Copolymer F was obtained in the same manner as in methyl methacrylate copolymer production example 1 except that 40 parts of methyl methacrylate and 60 parts of methyl acrylate instead of 15 parts of n-butyl acrylate were used. The test results such as the composition of the copolymer F are also shown in Table 1.
[0040]
Methyl methacrylate copolymer production example 7
The same procedure as in Production Example 1 of methyl methacrylate copolymer was carried out except that 70 parts of methyl methacrylate, 30 parts of ethyl acrylate instead of 15 parts of n-butyl acrylate, and 0.3 part of t-dodecyl mercaptan were added. A polymer G was obtained. The test results such as the composition of the copolymer G are also shown in Table 1.
[0041]
Methyl methacrylate copolymer production example 8
A copolymer H was obtained in the same manner as in the methyl methacrylate copolymer production example 1 except that ethyl acrylate was used instead of n-butyl acrylate. The test results such as the composition of the copolymer H are also shown in Table 1.
[0042]
The properties of the foamed molded product were examined by the following method.
1) Foamed cell state
The cut surface of the molded product is observed with an optical microscope and evaluated according to the following four grades.
A: The cell diameter is a fine and uniform state of 100 μm or less.
B: Cells that are destroyed and roughened are scattered.
C: Many cells are destroyed and roughened.
D: Most of the cells are destroyed and roughened.
2) Molded product surface properties
The surface of the molded product is visually and touched with the following four grades.
A: Smooth
B: Slightly skin-like
C: Skin
D: Many granular protrusions.
[0043]
3) True specific gravity and molded product specific gravity
Measured by the underwater replacement method according to JIS K 7112.
4) Molded product foaming ratio
Using the specific gravity value from the above measurement, the following formula is used.
Foaming ratio = true specific gravity / molded product specific gravity
5) Tensile strength
It is measured at a tensile speed of 10 mm / min using a JIS K 7113 No. 1 test piece.
[0044]
Examples 1-6, Comparative Examples 1-10
Each type and amount of ingredients shown in Table 2 were blended in a Henschel mixer as follows. Water vapor was volatilized while charging and mixing a vinyl chloride resin, a methacrylic ester resin (except for Comparative Example 1), wood flour, plasticizer, heat stabilizer, lubricant, filler and pigment. When the temperature rose to 140 ° C., the mixture was transferred to a cooling mixer and mixed. When the temperature dropped to 100 ° C., a foaming agent was added and the temperature was lowered to 60 ° C. (except for Comparative Example 8). .
The obtained powdery mixture was pelletized under the following conditions using a single screw extruder with a cylinder diameter of 65 mm. The water remaining in the wood flour was volatilized from the vent hole.

[0045]
The pellets thus obtained were subjected to extrusion foam molding under the following conditions using a single screw extruder having a cylinder diameter of 40 mm. In Comparative Example 8, a predetermined amount of trichlorofluoromethane was press-fitted from the vent hole of the cylinder with a high-pressure pump. Table 2 shows the characteristics of the molded product.

[0046]
[Table 1]

[0047]
note
MMA: Methyl methacrylate
MA: Methyl acrylate
EA: ethyl acrylate
n-BA: n-butyl acrylate
2-EHA: 2-ethylhexyl acrylate
ST: Styrene
[0048]
[Table 2]

[0049]
note
* 1 ZEST700L, Shin-Daiichi PVC Co., Ltd., vinyl chloride resin, average polymerization degree 680
* 2 Titanium oxide grain-attached wood powder, manufactured by Misawa Techno Co., Ltd., E60-T5-3, titanium oxide content 5% by weight, average particle size 60 μm, moisture content 5%
* 3 Selunt, manufactured by Shimada Shokai Co., Ltd., wood flour, average particle size 80μm, moisture 5% by weight
* 4 ACPE6A, manufactured by Allied Chemical
* 5 Tribasic lead sulfate / lead stearate composite heat stabilizer
* 6 Calcium carbonate CCR, manufactured by Shiraishi Calcium Co., Ltd., average particle size 0.08μm
* 7 Carbon Black (TPH0012, manufactured by Toyo Ink Manufacturing Co., Ltd.) / Condensed Azo Red (TXH4360, manufactured by the company) / Bisazo Yellow (TXH2110, manufactured by the company) composite pigment
[0050]
In Examples 1 to 6 molded using the composition having the requirements of the present invention, molded articles having good foam cell state and surface properties and having a sufficient foaming ratio were obtained. In particular, when lead stearate and polyethylene wax are used in combination as a lubricant, molded articles having further excellent foaming ratio and tensile strength can be obtained (Examples 1, 2 and 5).
However, in Comparative Example 1 using the copolymer D in which the glass transition point of the methyl methacrylate copolymer exceeds 85 ° C., a foam having a slightly skin-like surface with many cells that are broken and roughened is obtained. On the contrary, in Comparative Example 2 and Comparative Example 3 using a copolymer E or F having a glass transition point of less than 50 ° C., the foamed cell state was good, but the surface of the foam was crusty and unsatisfactory. became.
Comparative Example 2 and Comparative Example 4 using the copolymer E or G having a specific viscosity of the methyl methacrylate copolymer smaller than specified also give a skin-like foam surface, and the foaming ratio is low. On the contrary, Comparative Example 5 using the copolymer H having a specific viscosity larger than the specified value gave a result that the cell state of the foam was rough, the surface was slightly rough, and the foaming ratio was inferior.
[0051]
In Comparative Example 6 in which the number of blended parts of the methyl methacrylate copolymer was smaller than the specified value and in Comparative Example 7 having a larger number than the specified value, foams having a cell state and a rough surface were obtained.
In Comparative Example 8 where an organic compound having a low boiling point was used as the foaming agent, the foamed cells were often destroyed and roughened, and the surface of the molded product was also roughened like a crust.
The formulation lacking the plasticizer of component (E) gave a molded product whose surface was roughened like a crusted skin (Comparative Example 9). Moreover, the lack of plasticizer cannot be recovered by increasing the amount of lubricant (Comparative Example 10). When there are too many plasticizers, the retention of the cells is deteriorated, the cell state is deteriorated, the expansion ratio is lowered, and the tensile strength is lowered (Comparative Example 11).
[0052]
【The invention's effect】
By using the composition of the present invention, a vinyl chloride resin molded article having a uniform fine cell structure and a smooth skin, rich in wood texture and sufficient mechanical strength, suitable for building materials and furniture materials. Is obtained.
[Brief description of the drawings]
FIG. 1 is a graph showing the relationship between the specific viscosity y of a methyl methacrylate copolymer used in the present invention and the weight average molecular weight x in terms of standard polystyrene by GPC method.

Claims (2)

(A) 100 parts by weight of vinyl chloride resin, (B) containing 60% by weight or more of methyl methacrylate units, the glass transition point of the copolymer is 50 to 85 ° C., and the specific viscosity is 1.5 to 4.0. 7 to 30 parts by weight of a methyl methacrylate copolymer, (C) 0.1 to 3.0 parts by weight of a pyrolytic foaming agent, (D) 20 to 150 parts by weight of wood flour having an average particle size of 50 to 500 μm, and (E) A vinyl chloride resin composition comprising 1 to 20 parts by weight of a plasticizer. The vinyl chloride resin composition according to claim 1, further comprising (F) 0.5 to 10.0 parts by weight of metal soap and (G) 0.1 to 5.0 parts by weight of polyethylene wax.

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