JPH0673192A - Production of polyolefin-based resin composition - Google Patents

Abstract

PURPOSE:To produce the subject polyolefin-based resin composition excellent in workability, impact resistance, stiffness and surface properties from a polyolefin, a core-shell graft copolymer and an inorganic filler. CONSTITUTION:In production of a composition containing a polyolefin, a core- shell graft polymer and an inorganic filler in a specified ratio, this invented method for producing a polyolefin-based resin composition excellent in workability, impact resistance, stiffness and surface properties is carried out by preliminarily kneading a part of the polyolefin with the core-shell graft copolymer for preparation of a master batch and then kneading the resultant master batch with the remainder polyolefin and the inorganic filler.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a process for producing a polyolefin resin composition having good processability, impact resistance, rigidity and surface property, which is obtained from a polyolefin, a core-shell graft copolymer and an inorganic filler.

[0002]

2. Description of the Related Art Polyolefins are widely used because they are inexpensive and have excellent physical properties. However, for example, in polypropylene, (1) the viscosity and the tension at the time of melting are low, and therefore the vacuum formability of the sheet (hereinafter referred to as thermoformability), the calender formability,
Low blow moldability and foam moldability (2) Other rigid polystyrene, polyvinyl chloride, ABS
Compared with resin, etc., it has low defects (3) Low impact resistance at low temperature (4) Surface properties, that is, low surface gloss, hardness, paintability, etc.

In order to improve the processability of the polypropylene, a method of mechanically mixing a processability improver and the like is widely used. However, the addition of a proper amount is not sufficient to improve the processability. . If the mixing amount of the processability improving agent is increased in order to improve the defect that the effect of improving the processability is insufficient, a new defect occurs that the rigidity is lowered. Further, it has been attempted to improve the viscosity and the tension at the time of melting by increasing the molecular weight of polypropylene, but it is not preferable because extrusion molding which is an important processing method of polypropylene becomes difficult.

Inorganic fillers and the like have been added for the purpose of improving the inherently low rigidity of polyolefins and the reduction of rigidity due to the addition of processability improvers, but due to their poor compatibility with polyolefins and poor dispersion. However, it has a drawback that the surface property of a molded product (for example, an extruded sheet) is significantly lowered.

As a method of improving impact resistance, a method of introducing a rubber component obtained by a method such as mechanical mixing of rubber components or block copolymerization is widely used.
However, the introduction of the rubber component by mechanical mixing or block copolymerization cannot sufficiently control the dispersed particle size, so that the use efficiency of the rubber component is low and the impact resistance improving effect is insufficient. If a large amount of a rubber component is used to improve this drawback, there arises a problem that the rigidity is lowered.
Further, there is also a problem that the surface gloss is lowered due to the large particle size of the rubber component introduced.

Conventionally, core-shell type modifiers have been widely used as impact resistance improvers for polyvinyl chloride resins and the like. When this modifier is used, the rubber component (core portion) having a preset particle diameter can be efficiently dispersed, the rigidity can be suppressed and the impact resistance can be improved.

However, the compatibility of the core-shell type modifier with non-polar polyolefin is low and its use is limited.

In order to solve this problem, a method of adding a core-shell type modifier to polyolefin in the presence of a specific compatibilizer has been proposed (Japanese Patent Laid-Open No. 3-185037 and US Pat. No. 4,997,884). ), The synthesis of the compatibilizer is complicated, and there are problems that the use of the compatibilizer increases the cost and complicates the system.

As described above, workability, impact resistance, rigidity,
The fact is that a polyolefin resin composition having sufficiently good surface properties has not been obtained yet.

The present invention provides a method for obtaining a polyolefin resin composition having excellent processability, impact resistance, rigidity and surface property by mixing a core-shell graft copolymer and an inorganic filler with a polyolefin. It was made to develop.

[0011]

Means and Actions for Solving the Problems The present invention comprises (A) 100 parts of polyolefin (parts by weight, the same applies hereinafter), (B) rubber-like polymer (a) 40-95 parts of monomer (b) 60 to 5 parts total 100
To prepare a composition comprising 0.1 to 100 parts of a core-shell graft copolymer obtained by graft-copolymerization so as to form parts and (C) an inorganic filler of 0 to 400 parts, a part of the polyolefin and the core-shell are prepared. A polyolefin system having good processability, impact resistance, rigidity and surface property, which is characterized in that the graft copolymer is kneaded in advance to form a masterbatch, and the masterbatch and the remaining polyolefin and inorganic filler are kneaded. The present invention relates to a method for producing a resin composition.

When the core-shell graft copolymer is mixed with the polyolefin, a part of the polyolefin and the core-shell graft copolymer are kneaded in advance to form a masterbatch, and the masterbatch and the rest of the polyolefin and the inorganic filler are mixed. By kneading, the dispersibility of the core-shell graft copolymer in the polyolefin is improved, the tension during melting is increased, and the processability is improved. At the same time, a polyolefin resin composition having excellent impact resistance can be obtained. The presence of the core-shell graft copolymer also improves the dispersibility of the inorganic filler.

[0013]

EXAMPLES The polyolefin as the component (A) used in the present invention is not particularly limited, and any so-called polyolefin can be used. Specific examples of such a polyolefin include polypropylene, high-density polyethylene, low-density polyethylene,
Linear low density polyethylene, poly-1-butene, polyisobutylene, copolymers of ethylene and propylene in all ratios, ethylene and propylene in all ratios,
Ethylene-propylene-diene terpolymer having a diene content of 10% (% by weight or less) or less, polymethylpentene, ethylene or propylene and 50% or less of vinyl acetate, methacrylic acid alkyl ester, acrylic acid alkyl ester , A random copolymer with a vinyl compound such as aromatic vinyl, a block copolymer or a graft copolymer. Among the above-mentioned polyolefins, those containing 50% or more of propylene, and 100 parts of propylene-based polyolefin containing 50% or more of propylene and a mixture of 0 to 100 parts of polyethylene,
Further, those having a melt flow index of 4 or less at 230 ° C. have good kneading and dispersibility with the core-shell graft copolymer which is the component (B) and the inorganic filler which is the component (C). It is preferable for the effect expression of.

The core-shell graft copolymer which is the component (B) used in the present invention is a rubber-like polymer as a core,
It is a core-shell type graft copolymer having a vinyl-based hard polymer in the shell, and the core-shell graft copolymer as referred to in the present specification means that it is hard in the presence of a rubber-like polymer forming a core. This is a concept that includes graft copolymerization of shell components.

The core-shell graft copolymer (B) can be obtained by graft-copolymerizing the monomer (b) composed of a vinyl compound with the rubber-like polymer (a).

The rubber-like polymer (a) has a glass transition temperature of
Polymers at 25 ° C. or lower, for example, polybutadiene rubber, styrene-butadiene rubber, acrylonitrile-butadiene rubber, diene rubber such as n-butyl-butadiene rubber, n-butyl polyacrylate, 2-ethylhexyl acrylate Acrylic rubber, such as
Representative examples are ethylene-propylene-diene rubber, olefin rubber such as butyl rubber, and silicone rubber such as polydimethylsiloxane. These may be used alone or in combination of two or more. Particularly, those having a butadiene content of 50% or more are preferable from the viewpoint of compatibility with polyolefin.

Examples of the monomer (b) composed of a vinyl compound include aromatic vinyl compounds such as styrene and α-methylstyrene, alkyl methacrylates such as methyl methacrylate, ethyl methacrylate and n-butyl methacrylate, Representative examples are acrylic acid alkyl esters such as ethyl acrylate and n-butyl acrylate, and unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile. The aromatic vinyl compound is preferably styrene or α-methylstyrene, and the methacrylic acid alkyl ester is preferably a methacrylic acid alkyl ester having 1 to 4 carbon atoms. Further, a vinyl compound which is copolymerizable with the rubber-like polymer (a) or the monomer and has a reactive functional group such as an acid anhydride group, a carboxylic acid group, an amino group or a hydroxy group, for example, maleic anhydride. Acid, methacrylic acid, acrylic acid, methacrylamide, acrylamide, dimethylaminoethyl methacrylate, etc., hydroxyethyl methacrylate, hydroxyethyl acrylate, etc. can also be used as the monomer (b).
These monomers (b) may be used alone or in combination of two or more, if necessary.

The core-shell graft copolymer (B) comprises 40 to 95 parts, further 50 to 95 parts of the rubber-like polymer (a), 60 to 5 parts of a monomer (b) composed of a vinyl compound, and Can be obtained by graft copolymerizing 50 to 5 parts. Further, more preferably rubbery polymer (a) 40 to 95 parts, further 50
To 95 parts by weight of at least one of an aromatic vinyl compound and an alkyl methacrylate, 100 to 50%, further 100 to 60%.
% And other monomers 0 to 50%, more preferably 0 to 40%, and obtained by graft copolymerizing 60 to 5 parts, further 50 to 5 parts of the monomer (b). Rubbery polymer (a)
When it is less than 40 parts, the workability and impact resistance improving effects are lowered, and when it exceeds 95 parts, the graft copolymer is agglomerated, which is not preferable.

The core-shell graft copolymer (B) can be obtained by a conventional radical polymerization method such as a suspension polymerization method or an emulsion polymerization method. Therefore, the emulsion polymerization method is preferable. If necessary, the particles may be enlarged by adding an acid, a salt, a coagulant or the like. The particle diameter of the graft copolymer (B) is preferably 3 μm or less from the viewpoint of surface property.

The inorganic filler used in the present invention includes:
For example, heavy calcium carbonate, light calcium carbonate, talc, glass fiber and the like are mentioned as typical examples, and heavy calcium carbonate, light calcium carbonate and talc are preferable.

The polyolefin resin composition of the present invention, which has good processability, impact resistance, rigidity and surface property, is prepared by kneading the core-shell graft copolymer (B) with a part of the polyolefin in advance. It is obtained by making a batch and kneading the masterbatch with the rest of the polyolefin and the inorganic filler. The mixing ratio is 100 to 100 parts of the polyolefin (A), 0.1 to 100 parts of the core-shell graft copolymer (B), preferably 0.5 to 70 parts, and 0 to 400 parts of the inorganic filler (C), preferably 0. ~ 300 copies. When the amount of the graft copolymer is less than 0.1 part, the effect of improving the workability, impact resistance and surface property becomes insufficient, and 100
If it exceeds the range, the original properties of the polyolefin are lost, which is not preferable. Further, if the amount of the inorganic filler exceeds 400 parts, the surface property is deteriorated, which is not preferable.

The amount of polyolefin (A) to be pre-kneaded with the core-shell graft copolymer (B) is the total polyolefin.
(A) 80 to 0.1 part, more preferably 70 to 0.1 part, of 100 parts is preferable from the viewpoint of suppressing the decrease in the molecular weight of the polyolefin.

The proportion of the polyolefin (A) and the core-shell graft copolymer (B) in the master grasshopper is 5 to 95%, more preferably 5 to 95%, of the polyolefin (A).
〜80%, core-shell graft copolymer (B) 95〜
It will be 5%, and even 95-20%.

As a method for producing a masterbatch by previously kneading the core-shell graft copolymer (B) and a part of the polyolefin (A), there can be mentioned, for example, an extrusion kneading method and a roll kneading method. However, the method is not limited to these. Of these, the extrusion kneading method is preferable from the viewpoint of productivity.

The method of mixing the masterbatch thus produced with the remaining polyolefin and the inorganic filler is not particularly limited, and examples thereof include well-known methods such as extrusion kneading method and roll kneading method. To be

The polyolefin resin composition produced by the method of the present invention may further contain stabilizers, lubricants, etc., if necessary, and a core-shell type processability improver which has been used in conventional polyvinyl chloride resins. Can be added.
These may be added during the preparation of the masterbatch or the subsequent kneading.

The polyolefin-based resin composition obtained by the production method of the present invention can well control the viscosity and / or the tension at the time of melting, so that the draw-down of the sheet and the parison, the continuous foaming of the foam cells, etc. Can be improved, and processability such as thermoformability, calender moldability, blow moldability and foam moldability is improved. Further, the impact resistance of a molded article obtained by all processing methods such as injection molding, extrusion molding, thermoforming, calender molding, blow molding, foam molding, etc. can be improved.

The production method of the present invention will be described in more detail based on the following examples, but the present invention is not limited thereto.

Example 1 In the presence of 70 parts (solid content) of a polybutadiene rubber latex having a particle size of 2500 A, 30 parts of a monomer consisting of 15 parts of methyl methacrylate and 15 parts of styrene was graft-copolymerized by a usual emulsion polymerization method. Let Final addition rate is 98%, particle size is 26
It was 00A.

The obtained polymer latex was salted out by a usual method, dehydrated and dried. 60% of the obtained graft copolymer powder and 40% of Hypol-B-200 (polypropylene manufactured by Mitsui Petrochemical Industry Co., Ltd.) were mixed and the mixture was mixed with a twin screw extruder with a screw diameter of 44 mm and an L / D of 30 , 200 ℃, 100 rp
Extrusion kneading was carried out at m to prepare a masterbatch. 50 parts of the masterbatch, 80 parts of Hypol-B-200 and a ground calcium carbonate having a particle size of 1.8 μm surface-treated with fatty acid
50 parts were mixed and extruded and kneaded at 200 ° C. and 100 rpm with a twin-screw extruder having a screw diameter of 44 mm and an L / D of 30, and pelletized. The obtained pellets were roll-kneaded at 200 ° C. and press-formed to prepare various test pieces, and the following tests were conducted. The content of the formulation is shown in Table 1, and the obtained results are shown in Table 2.

(Izod impact resistance) ASTM-D 256, ASTM
-Tested according to -D 790.

(Drawdown) A sheet is formed into a 100 mm square and a thickness of 1.5 mm, and fixed with a clamp having an opening of 76 mm square,
Sheet drawdown was measured for 30 minutes in a 0 ° C. oven.

(Melt tension) The obtained pellets were heated at 200 ° C. using a Capillograph manufactured by Toyo Seiki Co., Ltd. and a die φ1.
mm × 10 mm, extrusion speed 20 mm / min, take-up speed 1 m /
Measured in minutes.

(Melt Flow Index) The pellets thus obtained were measured at 230 ° C. according to ASTM-D 1238.

(Dispersibility of Graft Copolymer) The obtained roll sheet was osmium-stained and observed with a transmission electron microscope. When the particles of the graft copolymer were independently dispersed, ○, partly aggregated. Those having a state were marked with Δ.

Comparative Example 1 30 parts of a graft copolymer obtained in the same manner as in Example 1,
100 parts of HYPOL-B-200 and 50 parts of ground calcium carbonate having a particle size of 1.8 μm surface-treated with fatty acid were kneaded together, and then mixed with a twin screw extruder with a screw diameter of 44 mm and L / D of 30.
The mixture was extruded and kneaded at 100 ° C. and pelletized. The same test as in Example 1 was performed using the obtained pellets. The results are shown in Table 2.

Example 2 50 parts of the masterbatch obtained in the same manner as in Example 1 and 80 parts of Hipol-B-200 were kneaded and pelletized in the same manner as in Example 1. The same test as in Example 1 was performed using the obtained pellets. The results are shown in Table 2.

Comparative Example 2 30 parts of a graft copolymer obtained in the same manner as in Example 1,
100 parts of HYPOL-B-200 was kneaded together, and the temperature was 200 ° C, 100 rpm with a twin-screw extruder with a screw diameter of 44 mm and an L / D of 30.
It was extruded and kneaded in to form pellets. The same test as in Example 1 was performed using the obtained pellets. The results are shown in Table 2.

[0039]

[Table 1]

[0040]

[Table 2]

The core-shell graft copolymer (B) is previously kneaded with a part of the polyolefin (A) to prepare a masterbatch, and the masterbatch and the remaining polyolefin (A) are mixed.
When the inorganic filler (C) is kneaded, the dispersibility of the core-shell graft copolymer (B) in the polyolefin (A) is improved and the viscosity by the Mettle Flow Index is higher than that of the one kneaded together. , The melt tension is increased,
It can be seen that the workability, especially the drawdown of the sheet, is improved. Further, it can be seen that impact resistance is also excellent. It can be seen that the same improvement effect can be obtained even in the system without the inorganic filler.

[0042]

EFFECT OF THE INVENTION When a polyolefin resin composition is produced by the method of the present invention, each component is dispersed more uniformly, and a composition having good processability is obtained. When a molded article is produced from this composition, impact resistance is improved. A product with excellent properties, rigidity and surface properties can be obtained.

Claims (6)

[Claims] 1. A total of 100 parts by weight of (A) 100 parts by weight of polyolefin, (B) 40 to 95 parts by weight of rubbery polymer (a) and 60 to 5 parts by weight of monomer (b). In producing a composition comprising 0.1 to 100 parts by weight of a core-shell graft copolymer obtained by graft copolymerization and 0 to 400 parts by weight of an inorganic filler (C), a part of the polyolefin and the core-shell graft copolymer are added. A masterbatch is prepared by kneading the coalescence in advance, and the masterbatch and the remaining polyolefin and the inorganic filler are kneaded, which is a processability,
A method for producing a polyolefin-based resin composition having good impact resistance, rigidity and surface properties. 2. The monomer (b) is at least one of an aromatic vinyl compound and an alkyl methacrylic acid ester.
The process according to claim 1, which comprises -50% by weight and 0-50% by weight of another vinyl compound copolymerizable therewith. 3. The method according to claim 2, wherein the aromatic vinyl compound is styrene and / or α-methylstyrene, and the methacrylic acid alkyl ester is a methacrylic acid alkyl ester having an alkyl group having 1 to 4 carbon atoms. 4. The process according to claim 1, wherein the rubber-like polymer (a) contains at least 50% by weight of butadiene. 5. The method according to claim 1, wherein the inorganic filler is calcium carbonate and / or talc. 6. A process according to claim 1, wherein the polyolefin contains at least 50% by weight of propylene units.