JPS62146947A - Polypropylene resin composition - Google Patents

Abstract

PURPOSE:To provide a polypropylene resin compsn. which gives moldings which have excellent rigidity and resistance to heat deformation and hardly cause secondary deformation, by blending a propylene/ethylene block copolymer having a specified composition and specified physical properties with an org. fiber. CONSTITUTION:A propylene (ethylene block copolymer consisting of 70-95wt% first-stage polymer composed of a propylene homopolymer satisfying the relationship represented by the formula, wherein P is an isotactic pentad fraction and MFR is a melt flow rate, and 30-5wt% first-stage to higher-stage ethylene/ propylene copolymer having an ethylene content of 3-16wt% based on the total polymer amount is prepd. [see, Japanese Patent Laid-Open No.201816/1983). The propylene/ethylene block copolymer is blended with 20-50wt% org. fiber (e.g., polyamide fiber, polyester fiber) to obtain the desired polypropylene resin compsn.

Description

[Detailed description of the invention] The present invention relates to polypropylene resin compositions.

More specifically, the present invention relates to a polypropylene resin composition that has excellent moldability and, when formed into a molded article, the molded article has excellent rigidity, heat deformation resistance, prevention of secondary deformation, sink mark, and warp deformation.

In recent years, materials such as automobile interior parts, parts for home appliances, and parts for OA equipment have increasingly been made of plastic, especially from the viewpoint of weight reduction and economic efficiency.
Polypropylene resins are preferably used because they are economical, have excellent appearance of molded products, have excellent strength, weather resistance, and durability.

However, interior parts and parts for home appliances molded using conventionally known polypropylene resins are subject to internal strain (residual stress) that occurs during the cooling process after molding. When the product is put into practical use,
When exposed to a temperature atmosphere of 0 to 120 degrees Celsius, internal strain is released, resulting in secondary deformation of the attached parts, resulting in a loss of commercial value. There is. To solve this problem, so-called inorganic filler polypropylene resin, which is a polypropylene resin filled with an inorganic filler, has been widely used. However, although the use of such inorganic filler-containing polypropylene resin improves the secondary deformability of the molded product, the surface of the molded product is easily scratched by foreign matter, and furthermore, the scratches turn white and impair the surface appearance. Moreover, it has the disadvantage that impact strength also decreases.

The present inventors have conducted extensive research in order to improve the drawbacks of the above-mentioned polypropylene resin compositions, that is, the tendency to cause secondary deformation. As a result, it was surprisingly found that the relationship between the isotactic pentad fraction of propylene homopolymer and the melt flow rate (MFR) was 1.0.
The first stage polymer having 0≧P≧0.015 log MF R+0.955 accounts for 70 to 95% of the total polymerization amount, and then ethylene and propylene of 30 to 5% of the total polymerization amount are added to 1% of the total polymerization amount. A predetermined amount of organic fiber is added to a propylene-ethylene block copolymer (hereinafter referred to as a specific propylene-ethylene block copolymer) that has been polymerized in more than one step and has an ethylene content of 3 to 16% by weight of the total polymerized amount. A composition obtained by blending a specific propylene-ethylene block copolymer with a predetermined amount of organic fibers and an inorganic filler has good moldability and when formed into a molded product. It was discovered that a molded article having excellent rigidity, heat deformation resistance, prevention of secondary deformation, sink marks, and warpage prevention can be provided, and the present invention was completed based on this knowledge.

As is clear from the above description, an object of the present invention is to have good moldability, and when molded into a molded product, to improve rigidity, heat deformation resistance, prevention of secondary deformation, sink marks, and warp deformation. An object of the present invention is to provide a polypropylene resin composition with excellent preventive properties.

The present invention has the following configuration.

(1) The relationship between isotactic pentad fraction (P) and melt flow rate (MFR) of propylene homopolymer is 1.00≧P≧0,015 log M F R+0
．． 955, the first stage polymer accounts for 70 to 95 of the total polymerization amount.
% by weight, and then polymerizes 6-30-5% by weight of ethylene and propylene in one or more steps, and the ethylene content is 3-16% by weight of the total polymerized amount.Propylene-ethylene block copolymer A polypropylene resin composition comprising a polymer and 20 to 5% by weight of organic fibers.

(2) The relationship between isotactic pentad fraction (I) and melt flow rate (MF) of propylene homopolymer is 1.00≧P≧0.015 log M F R-1-
0,955, and then polymerized in one or more steps with 30 to 5% by weight of ethylene and propylene, and the ethylene content is 3 to 16% by weight of the total polymerization.Propylene-ethylene block copolymer 20 to 5 organic fibers
A polypropylene resin composition containing 0% by weight and 5 to 30% by weight of an inorganic filler.

The propylene-ethylene block copolymer used in the present invention is a propylene-ethylene block copolymer (hereinafter referred to as a specific propylene-ethylene block copolymer) having a specific composition and physical properties.

Ordinary propylene-ethylene block copolymers are manufactured by a polymerization method that includes two or more polymerization steps, each of which includes a propylene homopolymer portion and an ethylene homopolymer portion, or an ethylene and propylene copolymer portion. Although it has better impact resistance than propylene homopolymer, it has the disadvantage that its heat distortion temperature is slightly lower than that of propylene homopolymer.

However, the specific propylene-ethylene block copolymer used in the present invention has an isotactic pentad fraction (P) of 1. oO≧P≧0.015 log M
It is a type of high-rigidity polypropylene related to FR100.955 (7), and the ethylene content in the remaining ethylene and propylene copolymer is 3% of the total amount of the polymer.
~16% by weight.

Such a copolymer and its production method are described, for example, in JP-A-58-2
It is disclosed in Japanese Patent No. 01816.

That is, (a) a reaction product of an organoaluminum compound (+) or an organoaluminum compound (1) and an electron donor (A) (a solid product (1) obtained by reacting Vll with titanium tetrachloride (C)); ), the solid product (seal) obtained by reacting the electron donor (A) and the electron acceptor (B) is further combined with an organoaluminum compound (ff) and an aromatic carboxylic acid ester (V) to produce the aromatic Molar ratio (V)/(u) of the group carboxylic acid ester and the solid product (1) = 0.
In the presence of a catalyst with a concentration of 1 to 100%, the total amount of polymerization was 70 to 10%.
95% by weight of propylene is polymerized, and then 30 to 5% by weight of the total polymerized amount of ethylene or ethylene and propylene are polymerized in one or more steps, and the ethylene content is 3%.
A propylene ethylene block copolymer for highly rigid molded articles, characterized in that the amount thereof is 20% by weight, and (b) an organoaluminum compound (I) or an organoaluminum compound (produced by reaction with an electron donor (A)). A solid product obtained by reacting compound (ff) with titanium tetrachloride (q), and further contains an electron donor (A) and an electron acceptor (]
Combining the solid product (1) obtained by reacting with 3) with an organoaluminum compound (ff) and an aromatic carboxylic acid ester (V), the molar ratio of the aromatic carboxylic acid ester and the solid product (summer) (V)/(I)=0.1~10
In the presence of a catalyst, 70 to 95% by weight of the total polymerized amount of propylene is polymerized, and then 30 to 95% of the total polymerized amount of propylene is polymerized.
5% by weight of ethylene or ethylene and propylene at 1
It is obtained by a method disclosed as a method for producing a propylene ethylene block copolymer for highly rigid molded articles, which is characterized in that the polymerization is carried out in more than one step to bring the ethylene content to 3 to 20% by weight.

The specific propylene-ethylene block copolymer used in the present invention described in the same publication is superior in various strengths and (double heat distortion temperature) to conventionally known propylene homopolymers or propylene-ethylene block copolymers. ing.

The organic fiber used in the present invention is one that does not decompose or melt at the melt-kneading temperature or molding knife Roe temperature and its residence time when melt-kneading or molding a polypropylene resin composition containing the organic fiber. There are no particular restrictions other than these, such as polyamide fibers, polyester fibers, polyimide fibers, polyvinyl alcohol fibers, polyvinylidene chloride fibers, ultra-high strength polyethylene fibers, polyacrylonitrile fibers, polyurethane fibers, and polyalkylene fibers. Zoate fibers, carbon fibers, phenolic fibers, rayon fibers, acetate fibers, cotton fibers, flax fibers, ramie fibers, jute fibers, wool fibers, silk fibers, and mixtures of two or more of these fibers can be used. The shape of the organic fiber used is not particularly limited and may be thread-like, woven or knitted fabric, or non-woven fabric. Woven-knitted fabrics or non-woven fabrics may be used by defibrating them into single fibers in advance. preferable.

Further, the length of the organic fiber used is preferably cut to a length of 1 to 5 mm, more preferably 1 to 3 mm.
A length of 0 questions, particularly 1 to 10 questions, is preferred. Furthermore, the thickness of the organic fiber used is preferably 0.5 to 20 deniers, more preferably 1 to 10 deniers.

The blending amount of the organic fiber is 20 to 50% by weight, more preferably 30 to 50% by weight. If the blend l is less than 20% by weight, it is not preferable because rigidity and secondary deformation cannot be prevented, and the fluidity of the molten resin decreases, resulting in a decrease in moldability.

The inorganic filler used in the present invention is a powdered inorganic filler, such as talc, calcium carbonate,
Calcium hydroxide, mica/barium sulfate, calcium silicate, clay, silica, alumina, wollastonite, magnesium carbonate, magnesium hydroxide, iron oxide, zinc oxide, titanium oxide, gypsum powder, and mixtures of two or more of these. be able to. Particularly preferred is talc.

The amount of the inorganic filler blended varies depending on the product performance required of the molded article, particularly the degree of improvement in rigidity and heat deformation resistance, but is usually 5 to 30% by weight. If the blending amount is less than 5% by weight, the effect of blending the inorganic filler will not be realized, and if it exceeds 30% by weight, the rigidity and heat deformation resistance will improve, but the impact strength will decrease, which is not preferable. .

The composition of the present invention may optionally contain various additives that are normally added to polypropylene resins, such as antioxidants, antistatic agents, ultraviolet absorbers, copper inhibitors, pigments, etc. .

The preparation of the compositions of the invention can be carried out, for example, by
Predetermined amounts of ethylene block copolymer pellets, organic fibers, and inorganic filler were mixed into a Hensel mixer (trade name),
Super mixer etc. (: Put, temperature 170-230℃
This can be carried out by heating, stirring, and kneading, or by melt-kneading and pelletizing a predetermined amount of each of the above-mentioned ingredients using a panburi mixer, roll, spindle or twin-screw extruder, coni-goo, or the like.

In producing the composition of the present invention, heat-kneading or melt-kneading must be carried out in such a way that the organic fibers blended during the above-mentioned heat-stirring kneading or melt-mixing do not melt or decompose (i.e., retain their original shape as fibers). Therefore, the heating stirring kneading temperature or melt kneading temperature is usually 170 to 230°C, more preferably 180 to 230°C.
A temperature of 00°C, especially 180 to 19°C is preferred. Furthermore, when molding the composition of the present invention by various molding methods, it is necessary to prevent the blended organic fibers from melting or decomposing at the temperature during the molding process. Temperatures below 230°C are preferred.

The polypropylene resin composition of the present invention can be used to manufacture various molded products by molding methods such as injection molding and extrusion molding, depending on the purpose.

Molded articles manufactured using the polypropylene resin composition of the present invention have higher rigidity, heat deformation resistance, and secondary It has excellent properties to prevent deformation, sink marks, and warp deformation, and is used in various product fields such as automobile interior parts, home appliance parts, and OA equipment parts (
Two suitable methods can be used.

Hereinafter, the present invention will be specifically explained with reference to Examples and Comparative Examples. The evaluation method used in the Examples and Comparative Examples was as follows.

1) Measurement of flexural modulus at stiffness temperatures of 23°C and 80°C (J
IS K'7203 (-compliant).

2) Heat deformation resistance Measurement of heat deformation temperature under a load of 18.5 Kqf /ctfl (according to JIS K720'2).

3) Secondary deformability A flat plate of 400 plates lengthwise, 80tnm width, and 3mm thickness was formed, and the plate was used as a test piece. Fix the two points on the left and right with screws and leave in an oven at 80℃ for 2 hours. After that, it is taken out from the open position, and the maximum gap between the test piece and the jig is immediately measured and taken as the amount of deformation A. Then, after leaving the test piece attached to the jig at room temperature for 24 hours,
The maximum gap between the test piece and the jig is measured and recorded as the amount of deformation B. (Secondly, remove the test piece from the jig, leave the test piece still on the jig, measure the maximum gap between the test piece and the jig, and record it as the amount of deformation C.
.

The smaller the amount of deformation, the better the ability to prevent secondary deformation.

4) Measurement of sink marks A test piece in the form of a flat plate measuring 90 mm long, 901 nm wide, and 2 mm thick with ribs 3 mm thick and 57 mm high and 1 g vertically attached was injection molded at a resin temperature of 200°C. The planar surface on the opposite side (back surface) of the rib attachment portion was visually observed, and the conspicuousness of sink marks was determined according to the following criteria.

○: Good surface condition with no visible sink marks.

×: Surface condition is poor with noticeable sink marks.

5) Measurement of warp deformation A flat plate of length 400 mm, width BO mm, thickness 3 mm was heated to a resin temperature of 20 mm.
A test piece is molded by injection molding at 0°C. After leaving the test piece at a temperature of 23°C and a relative humidity of 50% for 48 hours, the test piece was placed on a horizontal metal plate,
When a cylindrical metal weight of 1 piece with a diameter of 70mm and a height of 3ON+1 is placed on one end of the test piece, the amount of warping deformation is determined by measuring the gap between the other end of the test piece and the horizontal metal plate. It is recorded in units of wit.

Examples 1 to 5, Comparative Examples 1 to 7 As Examples 1 to 5, melt flow rate (MFR) 1
5f/10min, isotactic pentad fraction (P)
0.98, pellets of a specific propylene-ethylene block copolymer with an ethylene content of 8.5% by weight, and a blended fiber fabric consisting of 65% by weight of polyester and 35% by weight of cotton with a thickness of 1.5 denier as organic fibers. cut,
Defibrated organic fibers with a fiber length of 3 mm, Examples 2 to 3
Then, using talc with an average particle size of 2μ as an inorganic filler, each component was mixed in the Hensel mixer (trade name) (trade name) at a temperature of 180°C with two people in the proportions listed in Table 1 below.
The mixture was heated, stirred, and kneaded for 0 minutes to obtain a pellet-like composition.

In addition, as Comparative Examples 1 to 2, Comparative Example 1 used pellets of the same specific propylene-ethylene block copolymer as used in Examples 1 to 5 (2, glass fibers with an average diameter of 15 μm and an average length of 3 μm). Comparative Example 2
The specific propylene-ethylene block copolymer similar to that used in Examples 1 to 5 was blended with talc having an average particle size of 2μ at the blending ratio shown in Table 1 below, and a Hensel mixer (
Product name) and stirred and mixed for 10 minutes without heating immediately.
The obtained mixtures were melt-kneaded and extruded using a single-screw extruder with a diameter of 65 mm at a melt-kneading temperature of 250°C to obtain pellets.

As Comparative Examples 3 and 4, Comparative Example 3 has an MFR of 30? / 10
Pellets of a normal propylene-ethylene block copolymer having a P = 0.93 and an ethylene content of 8.5% by weight were crushed in the same manner as in Comparative Example 1 to obtain pellets.

In Comparative Example 4, the same ordinary propylene-ethylene block copolymer as used in Comparative Example 3 was blended with the same talc as used in Comparative Example 2 at the blending ratio shown in Table 1 below. Pellets were obtained by agitation mixing and melt cross-wire extrusion according to the standards.

As Comparative Examples 5 to 7, organic fibers similar to those used in Examples 1 to 5 were added to the same normal propylene-ethylene block copolymer as used in Comparative Examples 3 to 4, and in Comparative Example 7, talc, which was described later, was added. The compositions were blended in the proportions shown in Table 1 (2) and heated and kneaded in accordance with Examples 1 to 5 to obtain pellet-like compositions.

The pellets obtained in each of the practical examples and Comparative Examples 5 to 7 were injection molded at a resin temperature of 20° C. to prepare various test pieces of predetermined shapes.

Further, the pellets obtained in Comparative Examples 1 to 4 were injection molded at a resin temperature of 230° C. to create various test pieces of predetermined shapes.

Using the prepared test piece, the flexural modulus at 23°C and 80°C, 18.・The thermal deformation temperature, secondary deformability, sink marks, and warp deformability under load were measured for '51Qf/cI/. ・The results are summarized in Table 1.

As is clear from Table 1, the molded products obtained on each side using the χ11 composition of the present invention have a high rigidity (flexural modulus), heat deformation resistance, prevention of secondary deformation, sink marks, and warpage deformation. It can be seen that it has excellent prevention properties. On the contrary, Comparative Example 1, in which glass fiber was blended with a specific propylene-ethylene block copolymer instead of organic 47 fiber, and Comparative Example 3, in which glass fiber was blended with a normal propylene-ethylene block copolymer, were obtained. Molded products have excellent rigidity, heat deformation resistance, and sink mark prevention properties, but are extremely poor in preventing secondary deformation and preventing warping. Talc is added to a specific propylene-ethylene block copolymer. The molded products obtained in Comparative Example 2 in which talc was blended with a normal propylene-ethylene block copolymer and Comparative Example 4 in which talc was blended with a normal propylene-ethylene block copolymer had heat deformation resistance,
It can be seen that the prevention of secondary deformation and the prevention of sink marks and warping deformation are poor and there are practical problems.

In addition, the molded products obtained in Comparative Examples 5 and 6, in which organic fibers were blended with a normal propylene-ethylene block copolymer, had rigidity (flexural modulus), heat deformation resistance, secondary deformation prevention property, and warp deformation. The molded product obtained in Comparative Example 7, in which organic fibers and talc were blended with a normal propylene-ethylene block copolymer, was inferior to those obtained in Example 2. It can be seen that the rigidity (flexural modulus), heat deformation resistance, prevention of secondary deformation, and prevention of warp deformation are significantly inferior to molded products, which poses a practical problem.

As described above (2. Molded products molded using the composition of the present invention have excellent rigidity, heat deformation resistance, prevention of secondary deformation, prevention of sink marks and warping deformation, and are suitable for automobile interiors. It has been found that it can be suitably used for various molded products including parts for household appliances, parts for home appliances, and parts for OA equipment.

Patent applicant Chisso Co., Ltd. Company agent Patent attorney Yatabe Sasai Katsuhiko Nonaka

Claims (5)

[Claims] (1) The relationship between isotactic pentad fraction (P) and melt flow rate (MFR) of propylene homopolymer is 1.00≧P≧0.015logMFR+0.955
The first stage polymer is 70 to 95% by weight of the total polymerization amount, and then ethylene and propylene of 30 to 5% by weight of the total polymerization amount are polymerized in one or more steps, so that the ethylene content is 70 to 95% by weight of the total polymerization amount. A polypropylene resin composition comprising a propylene-ethylene block copolymer of 3 to 16% by weight and 20 to 50% by weight of organic fibers. (2) Organic fibers include polyamide fibers, polyester fibers, polyvinyl alcohol fibers, polyimide fibers, polyvinylidene chloride fibers, polyacrylonitrile fibers, polyurethane fibers, ultra-high strength polyethylene fibers, carbon fibers, polyalkylene paraoxy A patent claim using one selected from benzoate fibers, phenolic fibers, rayon fibers, acetate fibers, cotton fibers, flax fibers, ramie fibers, jute fibers, wool fibers, silk fibers, and mixtures of two or more of these fibers The polypropylene resin composition according to item (1). (3) The relationship between isotactic pentad fraction (P) and melt flow rate (MFR) of propylene homopolymer is 1.00≧P≧0.015logMFR+0.955
The first stage polymer is 70 to 95% by weight of the total polymerization amount, and then ethylene and propylene of 30 to 5% by weight of the total polymerization amount are polymerized in one or more steps, so that the ethylene content is 70 to 95% by weight of the total polymerization amount. A polypropylene resin composition comprising a propylene-ethylene block copolymer of 3 to 16% by weight, 20 to 50% by weight of organic fibers and 5 to 30% by weight of an inorganic filler. (4) Organic fibers include polyamide fibers, polyester fibers, polyvinyl alcohol fibers, polyimide fibers, polyvinylidene chloride fibers, polyacrylonitrile fibers, polyurethane fibers, ultra-high strength polyethylene fibers, carbon fibers, polyalkylene paraoxy A patent claim using one selected from benzoate fibers, phenolic fibers, rayon fibers, acetate fibers, cotton fibers, flax fibers, ramie fibers, jute fibers, wool fibers, silk fibers, and mixtures of two or more of these fibers The polypropylene resin composition according to item (3). (5) The polypropylene resin composition according to claim (3), using one selected from talc, mica, wollastonite, and a mixture of two or more thereof as the inorganic filler.