KR830001468B1 - Thermoplastic resin composition - Google Patents

Abstract

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Description

Thermoplastic Molding Composition

The present invention relates to a molding composition of a thermoplastic resin composed of polyolefin-based synthetic resin and waste paper fiber powder.

The core of the filler reinforcement plastic manufacturing technology lies in the filler dispersion in the synthetic resin, ie matrix resin, the geometry of the filler, the size of the filler, and the affinity between the filler and the main component resin. Selective use of resins has been common.

In recent years, a method of manufacturing interior materials by mixing materials made of vegetable fibers such as crests and sawdust with synthetic resins as a filler for synthetic resins has been developed.

However, among the vegetable fibers, waste paper fibers contain organic and inorganic substances used as binders or sizing materials in addition to pulp, which is a main component of paper, and additives such as calcium carbonate and talc are added. It is in a state that it is hardly used as a synthetic resin filler because it cannot obtain good physical properties.

Of course, it is true that a technique for manufacturing building interior materials by mixing vegetable fibrous materials, particularly crests, rice hulls, sawdust, etc., with synthetic resins is known, but in this case, the resins used are thermosetting resins such as phenol resins, urea resins, and melamine resins. In addition to having a polar or reactive atomic group or molecular group structure, in the prepolymerization state before curing, it has a low molecular weight molecular form and dilutes in a solvent so that it exists in solution and easily penetrates into wood fibers as well as cell cellulose. It was possible to obtain a product having excellent affinity for the Loose component and having no defects such as deterioration of physical properties.

However, even though the thermoplastic resin has a polar to reactive atomic group or molecular group, it is included in the main chain or arranged symmetrically, so that the thermoplastic resin not only has poor affinity with cellulose, sizing material, binder, etc. in wood fibers, especially paper components. Since the resin itself is a polymer having a large molecular weight and its method of use is dissolved in a solvent and made into a liquid, it is used by heating and melting instead of using it, so that it does not penetrate into paper fiber, resulting in worse physical properties when mixed with waste paper fiber. .

It is an object of the present invention to provide a thermoplastic resin molding composition having improved physical properties while improving the affinity of thermoplastic resin mixed with waste paper powder composed of cellulose, sizing material and inorganic filler.

The present invention improves physical properties by combining atomic or molecular groups having good affinity with waste paper to the molecular structure of polyolefin-based thermoplastic resins blended with waste paper including cellulose, sizing material and inorganic filler by chemical methods. It is composed of a method for preparing a thermoplastic molding composition.

In the present invention, the polyolefin thermoplastic resin means an amorphous or crystalline homopolymer or copolymer obtained by polymerizing a C ₂ -C ₈ α-mono-olefin (alkene) monomer.

Such polyolefin resins have poor paintability when coated with oil-soluble paints such as alkyd, acrylic, epoxy resin, and polyurethane-based paints. Therefore, the surface of the product is discharged or treated by other methods to improve the paintability, followed by coating treatment. It is customary to do that, the product produced by the synthetic resin composition produced by the method of the present invention has the advantage that the adhesiveness with the paint is good and as a result the paintability is also improved.

As a physical property improver of the thermoplastic resin used for this invention, the monomer which has a -COOH group in a molecular structure is used.

Typical examples of the above-described physical property improving agent include acrylic acid and methacrylic acid.

The composition of the present invention melts a polyolefin-based resin in a roll mill, half-barrier mixer, kneader, splatter screw extruder, single screw extruder, etc. It can be produced by a method of mechanically giving a shear action at a high temperature.

As described above, when a mechanical shearing action is performed by mixing a monomer, a polymerization initiator, and an activator, which is a physical property improving agent of a resin, a main chain or molecular chain is destroyed by mechanical shearing, or α-hydrogen is easily liberated to generate free radicals. Or a carboxyl group is produced, such that the free group or carboxyl group is combined with a monomer having affinity with the waste component is to improve the affinity with the waste paper.

In the present invention, a monomer, a polymerization initiator and an activator for the polyolefin resin may be added after melting of the polyolefin resin, but after blending these components together, the polyolefin resin may be melted and sheared. In addition, the blending of waste paper may be blended into the polyolefin resin prior to the addition of the monomer, may be discharged together with the monomer and other additives, and may be added while shearing.

The monomer used as the physical property improving agent in the present invention can be used as long as it has the reaction stage as described above and has affinity with the waste component. Among them, the low molecular material is good, but it can be used as the polymer material having the reaction stage. The monomer is used in an amount of about 1-10% by weight based on the polyolefin resin.

As typical examples of the low molecular weight having the reaction stage, methacrylic acid, acrylic acid, methylmethacrylic acid, metharolized phenol resins and the like are suitable.

The polymerization initiator used in the present invention mainly uses a peroxide system as a substance capable of generating a free group, and representative examples thereof include peroxides such as dicumyl peroxide and benzoyl peroxide, azo compounds, peresters, or the like. Use in combination. As for the thermal decomposition temperature of a polymerization initiator, about 50-250 degreeC is suitable.

The activator, or activator, uses metal oxides such as zinc oxide, magnesium oxide, calcium oxide, urine compounds, Lewis acid, and the like, and is used in the range of 0.5-5% of the monomer weight.

Example 1

Polypropylene (extrusion: MI 0.5) and waste paper pulverized powder are dry mixed at a weight ratio of 1: 1, and then put into a half-barrier mixer, kneaded at 170-200 ° for 10-20 minutes, and then the methacrylic acid, which is a physical property improving agent, is weighed in polypropylene. About 5% of the mixture and dicumyl peroxide / benzoyl peroxide / zinc oxide as a polymerization initiator in a ratio of 1: 1: 1: about 0.7% of methacrylic acid was added and kneaded for 10-20 minutes. It is made into pellets through a roll mill.

The prepared pellets were molded at 230 ° C. and 200 kg / cm ² in a hot press to make test specimens for physical properties.

Physical property test results are shown in Table 1.

Example 2

The pellets are prepared as follows using the materials used in Example 1 in the same proportions but using Buss MDK 46-E co-nearder instead of a Banbari mixer. The barrel temperature of the co-neander is fixed at 200 ° C., the die and screw temperature is maintained at 185 ° C., then a mixture of polypropylene and waste paper grinding is injected into the hopper and the mixture of monomer / peroxide / zinc oxide is placed in the barrel. Inject directly. The residence time in kneader is maintained for about 10 minutes.

The test results of the physical properties of the specimens formed from the prepared pellets are shown in Table 1.

Example 3

50 parts of propylene-ethylene block copolymer and 50 parts of waste paper powder are added to a half-barrier mixer and kneaded at 180-200 ° C. When the contents are molten, 1 part of dimethyl-P-octylphenol resin is added and kneaded for 2 minutes. 0.3 parts of tin chloride dihydrate, an activation promoter, is kneaded for 3-5 minutes, and then milled under a roll to form pellets. Specimens are made from the prepared pellets and tested for physical properties. The test results are shown in Table 1.

Example 4

The copolymer, the metharolized phenolic resin and the active promoter as used in Example 3 were mixed in the mixing ratio as in Example 3, added to a Henschel mixer, kneaded for 2 to 5 minutes, then introduced into a splatter-screw extruder, and extruder Knead while letting you stay within 10 minutes.

Specimens are made from the prepared compositions and tested for physical properties. The results are shown in Table 1.

TABLE 1

As can be seen from the results of Table 1 based on Examples 1 to 4, the present invention shows that the mold shrinkage rate, the flexural modulus, the flexural strength, and the heat deformation temperature are superior to those of the polypropylene alone.

Claims (2)

A thermoplastic resin molding composition obtained by mixing a polyolefin-based thermoplastic resin with a physical property improving agent having an atomic group or a molecular group having affinity for waste paper powder and waste paper component. The composition according to claim 1, wherein the physical property improving agent is selected from acrylic acid and methacrylic acid.