JPS58167637A - Preparation of molded polyolefin type resin article - Google Patents

Abstract

PURPOSE:To obtain a molded article useful for many fields, e.g. materials for housing several machines, due to the improved beautiful surfaces, by incorporating a composition consisting of a modified polyolefin resin, etc. with a polyolefin resin in a specific proportion, and injection molding the resultant mixture. CONSTITUTION:(A) 100pts.wt. composition consisting of a modified polyolefin type resin obtained by modifying a polyolefin with an unsaturated carboxylic acid and/or an anhydride thereof, or the modified polyolefin resin and a polyolefin resin and an organic and/or inorganic filler is incorporated with (B) 5- 50pts.wt. polyolefin type resin without kneading, and the resultant mixture is then injection molded to prepare a molded polyolefin resin article. Maleic acid (anhydride) or the anhydride thereof, is particularly preferred for the unsaturated carboxylic acid and used for modifying the polyolefin resin. Wood meal, calcium carbonate, etc. may be preferred for the filler.

Description

Detailed Description of the Invention [■] Object of the Invention The present invention relates to a method for producing a polyolefin resin molded article. More specifically, (A) a modified polyolefin resin obtained by modifying with an unsaturated carboxylic acid and/or its anhydride, or the modified polyolefin resin, the polyolefin resin, the organic filler, and /'i! A composition consisting of bamboo inorganic filler and (
'B) This relates to a method for producing a polyolefin resin molded product characterized by mixing and molding polyolefin resin without kneading, and the purpose is to provide a polyolefin resin molded product with an improved surface. That is.

BACKGROUND OF THE INVENTION Compositions obtained by mixing polyolefin resins with organic fillers and/or inorganic fillers have been industrially manufactured and widely used in many fields.

These compositions are intended to reduce the cost of the composition or to improve the physical properties of the olefin resin by mixing the filler with the polyolefin resin to increase the amount of the composition. However, these fillers are not only essentially incompatible with polyolefin resins, but also their fluidity decreases in proportion to the amount of fillers added. When such a composition is molded, the base resin (
Flow irregularities occur between the olefin resin (olefin resin) and the added filler, resulting in flow marks on the surface of the molded product. As a result, not only the appearance of the molded product deteriorates, but also the physical properties deteriorate, making it impossible to obtain a good molded product.

In order to improve or prevent these drawbacks, for example, lubricants such as fatty acids, metal soaps (for example, metal salts of carboxylic acids), and waxes may be added, or to improve the wettability and adhesion between the olefin resin and the filler. Widely used methods include the use of coupling agents such as silicon-containing organic compounds and titanium-containing organic compounds, or the introduction of reactive groups into the basic resin itself. However, although these methods can improve the effect to some extent, the improvement effect is not only unsatisfactory, but also technically complex, and it is difficult to improve economic efficiency, safety and health, and productivity. This is also an undesirable method for industrial production.

Structure of the Invention Based on the above, the present inventors conducted various searches to obtain a polyolefin resin molded product with an improved surface. (A) "Modification with an unsaturated carboxylic acid and/or its hydrate" (hereinafter referred to as "modified polyolefin resin")
Alternatively, 100 parts by weight of the modified polyolefin resin and a composition comprising the polyolefin resin and an organic filler and/or an inorganic filler and 5 to 50 parts by weight of the polyolefin resin (I3) are mixed without kneading and then injected. It was discovered that by molding, a molded product having a beautiful outer surface without the occurrence of flow marks could be obtained, and the present invention was achieved.

W] Effects of the Invention The polyolefin resin molded article of the present invention and its production exhibit the following effects (characteristics).

(1) In carrying out the present invention, modified polyolefin
Regarding the production of the composition of the filler and the filler and the molded product, as will be described later, conventional mixing is sufficient and the composition is easy to handle.

(2) The deterioration of the physical properties of the composition can be minimized, and the surface of the molded product can be beautifully improved.

(3) When painting the surface of a molded article, it can be applied beautifully without causing unevenness in the coating due to surface defects.

The surfaces of molded products and painted products obtained by the present invention are
As mentioned above, because of its beauty, it can be used in a wide variety of fields, and typical examples include consumer home appliances (e.g., televisions, videos), electric/electronic equipment (e.g., computers, communication equipment), and office equipment. Examples include housing materials for fax machines, word processors, etc., as well as automobile parts.

■ Detailed Description of the Invention (A) Modified Polyethylene Resin The modified polyolefin resin used in producing the compositions and molded articles of the present invention is a polyolefin resin described below, which is a polyolefin resin described below. acids or their anhydrides are preferred).

Representative examples of the unsaturated carboxylic acids or anhydrides thereof include monobasic carboxylic acids having at most 10 carbon atoms and at least one double bond (e.g., acrylic acid, methacrylic acid); dibasic carboxylic acids (e.g., maleic acid) and anhydrides of the dibasic carboxylic acids (e.g., maleic anhydride, anhydride, imitsuic acid) having at most 15 double bonds and at least one double bond. It will be done. Among these unsaturated carboxylic acids or their anhydrides, maleic acid and maleic anhydride are particularly preferred.

Modified polyolefin resins are generally obtained by treating polyolefin resins with unsaturated carboxylic acids and/or their anhydrides in the presence of organic peroxides.

Various known methods (for example, solution method, suspension method, melt method) can be used to produce the modified polyolefin resin of the present invention.
, any manufacturing method can be adopted.

Among these production methods, when polyolefin resin is modified with unsaturated carboxylic acid or its anhydride by a solution method, the polyolefin resin and unsaturated carboxylic acid and/or its anhydride are placed in a nonpolar organic solvent. A modified polyolefin resin can be obtained by further adding a radical initiator and heating at a high temperature.

In this case, the nonpolar organic solvents used include hexane, heptane, benzene, toluene, xylene, chlorobenzene, and tetrachloroethane.
As a radical initiator, 2,5-dimethyl-2,5-
Organic peroxides such as di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, and benzoyl peroxide may be mentioned.

Furthermore, the treatment temperature is a temperature at which the polyolefin resin used is dissolved, and is generally 110 to 160°C, particularly preferably 130 to 150°C.

In addition, when modifying polyolefin resins with unsaturated carboxylic acids or their anhydrides by the suspension method, polar solvents (
Generally, it is obtained by adding a polyolefin resin and an unsaturated carboxylic acid and/or its anhydride to water), adding the above-mentioned radical initiator, and treating under high pressure at a temperature of 100°C or higher. It will be done.

Furthermore, when modifying a polyolefin resin with an unsaturated carboxylic acid or its anhydride by a melting method, a melt mixer (for example, an extruder) used in the field of general synthetic resins is used to modify the polyolefin resin, Processing while melt-kneading unsaturated carboxylic acid and/or its anhydride and the above-mentioned radical generating agent.
: You can get it. The crosstalk temperature at this time varies depending on the type of polyolefin resin and radical generator used, but is in the temperature range from 2' to 300°C below the melting point of the polyolefin resin used. In the case of polyethylene, it is generally 120-270°C, and in the case of polypropylene, it is generally 160-270°C.
It is 0°0.

■) Polyolefin resins The polyolefin resins used for producing the above-mentioned modified polyolefin resins and the molded products described below include ethylene homopolymers, propylene homopolymers, and copolymers of ethylene and propylene. and/
or a copolymer of propylene and another α-olefin having at most 7 carbon atoms (the copolymerization ratio of α-olefin is at most 20% by weight), and ethylene and vinyl acetate,
Examples include copolymers with vinyl compounds such as acrylic esters and methacrylic esters (copolymerization ratio of vinyl compounds is at most 50 mol%, preferably at most 40 mol%). The molecular weight of these polyolefins is generally from 20,000 to 1,000,000, preferably from 20,000 to 500,000, and particularly preferably from 50,000 to 300,000.

In addition, ethylene homopolymers, propylene homopolymers, copolymers of ethylene and propylene, and copolymers of ethylene or propylene with other α- Copolymers with olefins are preferred.

(q Inorganic fillers and organic fillers The inorganic fillers and organic fillers used to produce the composition of the present invention are those commonly used in synthetic resins and rubbers. Metals with chemical compositions such as aluminum, copper, iron, and silver, and alloys containing these as main components, as well as aluminum oxide, its hydrates, aluminum silicate, antimony oxide, barium titanate, colloidal silica, calcium carbonate, and sulfuric acid. calcium sulfate, iron oxide, asbestos, carbon black, graphite, shirasu balloon, fly ash, glass fiber, lithium silicate/aluminum clay, mica, silica, silica stone, diatomaceous earth, silicon carbide, talc, asbestos, Compounds such as zirconium oxide, zirconium silicate, molybdenum disulfide, titanium oxide and glass spheres, double salts and mixtures thereof are mentioned.Organic fillers include spherical phenols, linters, linens, etc. , silk, viscose, polyacetate, polyamide fiber, polyester fiber, vinylon fiber, wood flour, waste paper, rice husk, jute, cork powder and fiber flock. )
, flat (for example, mica), acicular (for example, asbestos), spherical (for example, glass bulbs), fibrous (various types of fibers), and fibrous (for example, glass fiber mat). Among the inorganic fillers, powder, plate-like and spherical materials preferably have a diameter of I mm or less. Further, as for the organic filler, one having a mesh pass of 12 is desirable, and one having a pass of 45 mesh is particularly suitable. Furthermore, the organic or inorganic fibrous material preferably has a diameter of 1 to 50 microns and a length of 01 to 6 mm.

The organic filler must be such that it does not melt (its melting point is higher than the melting temperature and molding temperature) during the melt-kneading and molding processes described below.

(g) Production of composition To produce the composition of the present invention, the modified polyolefin resin or the modified polyolefin resin and polyolefin resin are uniformly mixed with an organic filler and/or an inorganic filler. You can get it by doing this.

(1) Composition ratio The composition ratio of the modified polyolefin resin and the polyolefin resin in the composition is generally 20 to 95% by weight in total, and 30 to 90% by weight.
is preferred, particularly 40 to 80% by weight. If the composition ratio of the modified polyolefin resin and the polyolefin resin is less than 20% by weight, it becomes difficult to produce a uniform composition with the organic filler and/or inorganic filler. On the other hand, if it exceeds 95% by weight, it is not preferable because the effect of reducing costs and improving physical properties is small.

In the present invention, the modified polyolefin resin and the unsaturated carboxylic acid and/or
or the proportion of its anhydride is 101 to 10 mmol (preferably 5 x 10'' to 5 mmol, preferably 2 x 10-'
2 mmol).

(2) Production method The composition of the present invention can be produced by any method commonly used for producing compositions of modified polyolefin resins and fillers. Examples of this method include tri-blending using a mixer such as a Henschel mixer, and melt-kneading using a mixer such as a Banbury mixer, kneader, roll mill, and screw extruder. At this time, a more uniform composition can be obtained by triblending in advance and further melt-kneading the resulting mixture. In this case, it is generally melt-kneaded and then formed into pellets.
It is used for manufacturing the molded product described below.

This composition is produced by uniformly mixing a modified polyolefin resin or a polyolefin resin and an organic filler and/or an inorganic filler, and further includes oxygen and heat. Also included are stabilizers against.

Additionally, additives such as light stabilizers, metal deterioration inhibitors, electrical property improvers, adhesion improvers, flame retardants, foaming agents, lubricants, plasticizers and colorants may be incorporated.

(Production of homogeneous molded product) A molded product can be produced by mixing the composition obtained as described above and a polyolefin resin without kneading and injection molding the mixture. Alternatively, part or all of the above-mentioned modified polyolefin resin may be used.

(1) Molding ratio In producing the molded product of the present invention, the ratio of polyolefin resin to 100 parts by weight of the composition is 5 to 50 parts by weight, preferably 5 to 50 parts by weight, especially 7 to 50 parts by weight.
35 parts by weight is preferred.

unacceptable. On the other hand, if the amount is 50 parts by weight or more, the improvement effect is sufficiently recognized, but the initial objective cannot be achieved without significantly reducing the proportion of the filler in the molded product and further changing its physical properties in the same way. I can't.

In addition, fillers (organic fillers and inorganic fillers) occupying in the molded product obtained from the composition and polyolefin resin.
The amount is preferably 3 to 35 volumes, particularly preferably 5 to 30 volumes.

(2) Manufacturing method A good molded product cannot be obtained if the composition and the polyolefin resin are melt-kneaded.

That is, it is necessary to triblend them. Even if it is melted and kneaded, it will not be possible to obtain a molded product that achieves the object of the present invention. A molded article can be produced from the mixture thus obtained by a commonly used injection molding method. At this time, the polyolefin resin mixed with the composition may contain additives other than the filler contained in the composition. Further, it is usually necessary to include a stabilizer. In this case, the polyolefin resin used to produce the molded product may be of a different type from the modified polyolefin resin used to obtain the composition, but if the same type is used, it will work fine. [For example, if modified polyethylene (including copolymers) is used in the production of the composition, it is desirable to use polyethylene or its modified product in the production of the molded product].

Whether the composition is melt-kneaded or the molded article is injection molded, the process must be carried out at a temperature equal to or higher than the softening point of the polyolein-based resin or its modified material. No, but 25
If the heating is carried out at a temperature of 0° C. or higher, a part of the first polynofin resin or its modified product may undergo thermal deterioration. Therefore, it is natural that the process must be carried out at a temperature below this temperature.

EXAMPLES EXAMPLES AND COMPARATIVE EXAMPLES The present invention will be explained in more detail with reference to Examples below.

In addition, in the examples and comparative examples, tart flow
The index (hereinafter referred to as MFIJ) is JIS K.
-6758, at a temperature of 230° C. and a load of 2.16 kg. In addition, the melt index (hereinafter referred to as "M, 1.") is JIS K-6.
760, the temperature is 1'90°C and the load is 2
．． Measurement was carried out under the condition of 16 kg.

Example 1 As a polyolefin resin, the density is 0.9001/c
d propylene homopolymer (Mll”IO, 5g/
10 minutes, hereinafter referred to as rPP(a)J) 100 parts by weight, 0
01 parts by weight of 2,5-dimethyl-2,5-di(butylperoxy)hexane (as an organic peroxide) and maleic anhydride were pre-triblended for 5 minutes using a Henschel mixer. The resulting mixture was melt-kneaded using an extruder (diameter: 40 mm, resin temperature: 220°C) to produce modified polypropylene (hereinafter referred to as "modified PP").
(7)] was created. The content of maleic anhydride in this modified PP (], ) was 0.6% by weight.

50 parts by weight of the modified PP (1), 30 parts by weight of wood flour (100 mesh pass) as a filler, and 20 parts by weight of calcium carbonate (average particle size 10 microns) were mixed for 3 minutes using a Henschel mixer (tri-blend). did. The resulting mixture was melt-kneaded using a twin-screw vented extruder (diameter 30 mm) [vent suction (600 mm Hg)].
, resin temperature 200°C].

For 100 parts by weight of this pellet, 20 parts by weight of propylene homopolymer [MFI 10g710min, hereinafter referred to as rPP
(referred to as dLJ) was added and mixed for 10 minutes (tri-blend) using a tumbler.
using an injection molding machine (resin temperature 200°C)
A radio box (length 100 mm, width 200 mm, depth 60 mm, average thickness 3 mm) was molded. As a result, a beautiful molded product was obtained with no flow marks. -1: This molded product was painted silver (
Micron: #-3000') was applied from 1 onwards, and the painted surface was uniform and beautiful.

Comparative Example 1 The pellets obtained in Example 1 were injection molded in the same manner as in Example 1. As a result, many flow marks were generated due to uneven flow of filler such as wood powder, especially on the depth surface. Furthermore, when this molded product was painted with silver in the same manner as in Example 1, flow marks also appeared on the painted surface, and a beautiful product could not be obtained.

Examples 2 to 10 Instead of PP (a) used as the polyolefin resin in producing the modified PP (1) of Example 1, a propylene homopolymer (MFI) having a density of 0900 g/d was used.
1. Q,! 7/1.0 minutes, hereinafter r P P (1)) -
1,! = say], propylene-ethylene block copolymer CMFT LO with a density of 0900 g/Cr1l
j; l/10 min, ethylene content 15% by weight, below [
PP(C)J], an ethyl L/7-butene-1 copolymer [M, 1. ]
(11110 minutes or less PE(a)) and density is 0
．． Ethylene homopolymer CM with 951 g/d ethylene
,I.

Tri-blending was carried out under exactly the same conditions as in Example 1, except that 7.0 g was used for 710 minutes and 100 parts by weight of each [hereinafter referred to as PE (b)] was used. Each of the obtained mixtures was melt-kneaded in the same manner as in Example 1 to produce a modified polyolefin resin. Table 1 shows the MFI or M, 1° of each of the obtained modified polyolefins and their abbreviations.

Modified polyolefin resins whose blending amounts are shown in Table 2 [Modified PP (1), Modified PP (2), Modified PP
(3) Modified PE (1) or modified PE (2)) or modified polyolefin resin and polyolefin resin are used, and the above-mentioned calcium carbonate (hereinafter referred to as "CaCO3"), barium sulfate ( Average particle size 5
microns (hereinafter referred to as "BaSO4") or talc (average particle size 30 microns), or the above-mentioned wood flour, jute (diameter 5 to 200 microns, length
Tri-blending was performed in advance in the same manner as in Example 1 using 0.1 to 2 mm) or waste paper (50 mesh bath product) in the amounts shown in Table 2. Each of the obtained mixtures was melt-kneaded under the same conditions as in Example 1 to produce pellets.

The obtained pellets [composition Pl] were used in Comparative Example 1
A radio box was manufactured by injection molding under the same conditions. Each of the resulting radio boxes had a large number of flo marks on all surfaces. Furthermore, when silver painting was applied, flow marks were also generated on the painted surface (Comparative Examples 2 to 7).

100 parts by weight of each of the pellets (compositions) obtained as described above and a polyolefin resin (the blending amounts are shown in Table 3) were triblended in the same manner as in Example 1. Each of the obtained mixtures was injection molded under the same conditions as in Example 1 to produce radio boxes. The surfaces of all radio boxes were painted silver in the same manner as in Example 1. The surface of each radio box was clean and free of flow marks. Furthermore, the silver painted surface was uniform and beautiful.

Table 3 Patent Applicant Showa Denko Co., Ltd. Agent Patent Attorney Sei Kikuchi Procedural Amendment (Spontaneous) May 74, 1980 Commissioner of the Patent Office Shima 1) Haruki Tono 1 Indication of Case 1988 Patent Application No. No. 50004 No. 2 Name of the invention 3 Relationship to the case of the person making the amendment Patent applicant 4, agent (zip code 105) Residence 13-9 Shiba Daimon-chome, Minato-ku, Tokyo Showa Denko K.K. internal telephone number Tokyo 432-51 .11 (Main representative) name (
7037) Patent Attorney Sei Kikuchi - 5 Date of amendment order Issued 6 Column 7 for "Detailed Description of the Invention" of the specification subject to amendment 7 Contents of amendment (1) 1 water in line 6 on page 4 of the specification The phrase ``denatured with anhydride'' is corrected to ``denatured with anhydride.''

(2) On the second line of page 6 of the same document, the text "r(A) Modified polyethylene resin" has been corrected to read "1(A) Modified polyolefin resin."

(3) On page 12, line 4 of the same page, the statement ``Does not melt when exposed, but tends to melt'' has been corrected to ``Does not melt when exposed.''

Claims (1)

[Scope of Claims] (5) A modified polyolefin resin obtained by modifying with an unsaturated carboxylic acid and/or its anhydride, or the modified polyolefin resin and the polyolefin resin and an organic filler and/''!, bamboo 1. A method for producing a polyolefin resin molded article, which comprises mixing 100 parts by weight of a composition comprising an inorganic filler and 5 to 50 parts by weight of (B) polyolefin resin without kneading and injection molding the mixture.