JP3202803B2 - Method for producing polyolefin resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polyolefin resin composition having good processability, impact resistance, rigidity and surface properties obtained from a polyolefin, a core-shell graft copolymer and an inorganic filler.

[0002]

BACKGROUND OF THE INVENTION Polyolefins are widely used because they are inexpensive and have excellent physical properties. However, for example, in the case of polypropylene, (1) the viscosity and tension at the time of melting are low, so that the sheet has vacuum formability (hereinafter referred to as thermoformability), calenderability,
Low blow moldability, foam moldability, etc. (2) Other rigidity polystyrene, polyvinyl chloride, ABS
(3) Low impact resistance at low temperatures (4) Poor surface properties, that is, low surface gloss, hardness, paintability, etc.

[0003] In order to improve the processability of the polypropylene, a method of mechanically mixing a processability improving agent or the like is widely and generally employed, but the effect of improving the processability is insufficient if added moderately. . If the mixing amount of the processability improver is increased in order to improve the disadvantage that the processability improvement effect is insufficient, a new disadvantage occurs that the rigidity is reduced. Although the viscosity and tension at the time of melting are also improved by increasing the molecular weight of polypropylene, extrusion molding, which is an important processing method of polypropylene, becomes difficult, which is not preferable.

[0004] In order to improve the low rigidity inherent in polyolefins and the reduction in rigidity due to the addition of processability improvers, inorganic fillers and the like are added, but the compatibility with polyolefins is low, and poor dispersion due to poor dispersion. However, there is a disadvantage that the surface properties of a molded article (eg, an extruded sheet) are significantly reduced.

As a method for improving impact resistance, a method of introducing a rubber component obtained by a method such as mechanical mixing or block copolymerization of a rubber component 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 effect of improving the impact resistance is insufficient. If a large amount of the rubber component is used to improve this disadvantage, there is a problem that the rigidity is reduced.
There is also a problem that the surface gloss is reduced due to the large particle diameter of the rubber component to be introduced.

Heretofore, core-shell type modifiers have been widely used as impact modifiers such as polyvinyl chloride resins. When this modifier is used, a rubber component (core portion) having a predetermined particle diameter can be efficiently dispersed, and a reduction in rigidity can be suppressed to improve impact resistance.

However, core-shell type modifiers have low compatibility with non-polar polyolefins, and their use is limited.

In order to solve this problem, a method has been proposed in which a core-shell type modifier is added to a polyolefin in the presence of a specific compatibilizer (Japanese Patent Application Laid-Open No. 3-185037, US Pat. No. 4,997,843). ), The synthesis of the compatibilizer is complicated, and the use of the compatibilizer raises costs and complicates the system.

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

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

[0011]

The present invention comprises (A) 100 parts of a polyolefin (parts by weight, the same applies hereinafter), (B) 40 to 95 parts of a rubbery polymer (a) and monomer (b) 60 to 5 parts total 100
In preparing a composition comprising 0.1 to 100 parts of a core-shell graft copolymer obtained by graft copolymerization to give 0 parts to 400 parts of an inorganic filler (C), a part of the polyolefin and a core shell A polyolefin-based material having good processability, impact resistance, rigidity and surface properties characterized by kneading the graft copolymer in advance to form a masterbatch and kneading the masterbatch with the remaining polyolefin and inorganic filler. 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. By kneading, the dispersibility of the core-shell graft copolymer in the polyolefin is improved, the tension at the time of melting is increased, and the processability is improved. At the same time, a polyolefin-based 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]

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

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

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

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

Examples of the monomer (b) comprising 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 include alkyl acrylates such as ethyl acrylate and n-butyl acrylate, and unsaturated nitrile compounds such as acrylonitrile and methacrylonitrile. Styrene and α-methylstyrene are preferable as the aromatic vinyl compound, and alkyl methacrylate having 1 to 4 carbon atoms is preferable as the alkyl methacrylate. Further, a vinyl compound copolymerizable with the rubbery polymer (a) or the monomer and having a reactive functional group such as an acid anhydride group, a carboxylic acid group, an amino group, or a hydroxy group, such as maleic anhydride Acids, methacrylic acid, acrylic acid, methacrylamide, acrylamide, dimethylaminoethyl methacrylate and the like, hydroxyethyl methacrylate, hydroxyethyl acrylate and the like 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) is composed of 40 to 95 parts, more preferably 50 to 95 parts, of the rubbery polymer (a) and 60 to 5 parts of the monomer (b) composed of a vinyl compound. Can be obtained by graft copolymerization of 50 to 5 parts. Further, more preferably 40 to 95 parts of the rubbery polymer (a), furthermore 50
To 95 parts by weight of at least one of an aromatic vinyl compound and an alkyl methacrylate, 100 to 50%, more preferably 100 to 60%.
% And other monomers from 0 to 50%, and more preferably from 0 to 40%, by graft copolymerizing 60 to 5 parts, and more preferably 50 to 5 parts of the monomer (b). Rubbery polymer (a)
If the content is less than 40 parts, the effect of improving workability and impact resistance is reduced, and if it exceeds 95 parts, the graft copolymer is undesirably aggregated.

The core-shell graft copolymer (B) can be obtained by a conventional radical polymerization method, for example, a polymerization method such as a suspension polymerization method or an emulsion polymerization method. Therefore, the emulsion polymerization method is preferred. 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 properties.

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

The polyolefin resin composition having good processability, impact resistance, rigidity and surface properties according to the production method of the present invention is obtained by kneading a core-shell graft copolymer (B) in advance with a part of polyolefin, It is obtained by making a batch and kneading the masterbatch with the remaining polyolefin and inorganic filler. The mixing ratio is 0.1 to 100 parts, preferably 0.5 to 70 parts, and the inorganic filler (C) is 0 to 400 parts, preferably 0 to 100 parts of the polyolefin (A). ~ 300 copies. When the amount of the graft copolymer is less than 0.1 part, the effects of improving processability, impact resistance, and surface properties become insufficient, and
If the amount exceeds the above range, the inherent characteristics of the polyolefin are lost, which is not preferable. On the other hand, if the amount of the inorganic filler exceeds 400 parts, the surface properties are undesirably reduced.

The amount of the polyolefin (A) to be kneaded in advance with the core-shell graft copolymer (B) is the total amount of the polyolefin.
(A) 80 to 0.1 part, more preferably 70 to 0.1 part, out of 100 parts is preferred from the viewpoint of preventing the molecular weight of the polyolefin from being reduced.

The blending ratio of the polyolefin (A) and the core-shell graft copolymer (B) in the master grasshopper is 5 to 95%, more preferably 5 to 95%.
Core-shell graft copolymer (B) 95-
5%, and even 95-20%.

The method for preparing a master batch by previously kneading the core-shell graft copolymer (B) and a part of the polyolefin (A) includes, for example, an extrusion kneading method and a roll kneading method. However, the present invention is not limited to these methods. Among these, the method of extrusion kneading is preferred from the viewpoint of productivity and the like.

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

The polyolefin resin composition of the present invention may further contain, if necessary, a stabilizer, a lubricant, etc., or a core-shell type processability improver conventionally used in polyvinyl chloride resins. Can be added.
These additives may be added at the time of preparing a master batch or at the time of kneading thereafter.

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

Hereinafter, the production method of the present invention will be described in more detail with reference to Examples, but the present invention is not limited by these.

Example 1 Polybutadiene rubber latex having a particle size of 2500 A (polymerizer)
In addition, 250 parts of pure water, 0.2 parts of potassium persulfate and t-dodecyl
Charge 0.1 part of mercaptan and vacuum pump the air in the vessel
And then 2 parts of sodium oleate and
Charge 10 parts of Tadiene, then raise the temperature to 50 ° C for 48 hours
In the presence of 70 parts (solid content), 30 parts of a monomer composed of 15 parts of methyl methacrylate and 15 parts of styrene were graft-copolymerized by a usual emulsion polymerization method. . The final addition rate was 98% and the particle size was 2600A.

The obtained polymer latex was salted out by a conventional method, dehydrated and dried. 60% of the obtained graft copolymer powder and 40% of Hypol-B-200 (polypropylene manufactured by Mitsui Petrochemical Industries, Ltd.) were mixed, and the mixture was extruded with a twin screw extruder having a screw diameter of 44 mm and an L / D of 30. , 200 ° C, 100 rp
The mixture was extruded and kneaded to prepare a master batch. And the master batch, 50 parts of beauty particle child size 1.8 [mu] m Oyo 80 parts Haiporu -B-200, and a heavy calcium carbonate (Maruo Calcium Co., Ltd. Snow Light SSS) 50 parts of surface-treated with a fatty acid The mixture was mixed, 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 to form a pellet. Kneading, pressing forming the obtained pellets at 200 ° C.
By shaping , various test pieces were prepared, and the following tests were performed. The composition is shown in Table 1 and the obtained results are shown in Table 2.

(Izod impact resistance) ASTM-D256, ASTM
The test was performed according to -D790.

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

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

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

(Dispersibility of Graft Copolymer) The obtained roll sheet was stained with osmium and observed with a transmission electron microscope. Those having a state were marked with △.

Comparative Example 1 30 parts of the graft copolymer obtained in the same manner as in Example 1,
100 parts of Hypol-B-200 and 50 parts of heavy calcium carbonate having a particle diameter of 1.8 μm, surface-treated with a fatty acid, are kneaded in a lump.
The mixture was extruded and kneaded at 100 ° C. and 100 rpm to form pellets. The same test as in Example 1 was performed using the obtained pellets. Table 2 shows the results.

Example 2 In the same manner as in Example 1, 50 parts of the master batch and 80 parts of Hypol-B-200 obtained in the same manner as in Example 1 were kneaded and pelletized. The same test as in Example 1 was performed using the obtained pellets. Table 2 shows the results.

Comparative Example 2 30 parts of the graft copolymer obtained in the same manner as in Example 1,
100 parts of Hypol-B-200 are kneaded in a lump, and a twin screw extruder with a screw diameter of 44 mm and L / D of 30 is used at 200 ° C and 100 rpm.
And extruded and kneaded to form pellets. The same test as in Example 1 was performed using the obtained pellets. Table 2 shows the results.

[0039]

[Table 1]

[0040]

[Table 2]

The core-shell graft copolymer (B) is previously kneaded with a part of the polyolefin (A) to form a masterbatch, and the masterbatch and the remaining polyolefin (A)
The kneaded inorganic filler (C) improves the dispersibility of the core-shell graft copolymer (B) in the polyolefin (A), and the viscosity measured by , The melt tension is increased,
It can be seen that the workability, especially the drawdown of the sheet, has been improved. Also, it is understood that the impact resistance and the like are excellent. It can be seen that a similar improvement effect can be obtained in a system without an inorganic filler.

[0042]

According to the present invention, when a polyolefin resin composition is produced by the production method of the present invention, each component is more uniformly dispersed, and a composition having good processability is obtained. A product with good properties, rigidity and surface properties can be obtained.

────────────────────────────────────────────────── (5) References US Patent 4,957,974 (US, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08J 3/22

Claims (6)

(57) [Claims] (1) 100 parts by weight of a polyolefin, (B) 40 to 95 parts by weight of a rubbery polymer (a), and 60 to 5 parts by weight of a monomer (b) so that the total amount becomes 100 parts by weight. In producing a composition comprising 0.1 to 100 parts by weight of the core-shell graft copolymer obtained by graft copolymerization and 0 to 400 parts by weight of the inorganic filler (C), a part of the polyolefin and the core-shell graft copolymer Processability characterized by kneading the coalesced in advance to form a masterbatch and kneading the masterbatch with the remaining polyolefin and inorganic filler,
A method for producing a polyolefin resin composition having good impact resistance, rigidity and surface properties. 2. The method according to claim 1, wherein the monomer (b) is at least one of an aromatic vinyl compound and an alkyl methacrylate.
2. The process according to claim 1, comprising from 50 to 50% by weight and from 0 to 50% by weight of other vinyl compounds copolymerizable therewith. 3. The process according to claim 2, wherein the aromatic vinyl compound is styrene and / or α-methylstyrene, and the alkyl methacrylate is an alkyl methacrylate having 1 to 4 carbon atoms in the alkyl group. 4. The process according to claim 1, wherein the rubbery 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. The process according to claim 1, wherein the polyolefin contains at least 50% by weight of propylene units.