JPH0374454A - Polypropylene composite resin composition for stamping forming - Google Patents

Abstract

PURPOSE:To provide a composition having excellent stamping formability and capable of giving form integrated with a singly layered or plurally layered surface by compounding a crystalline ethylene.propylene block copolymer having a specific mol.wt. distribution with an amorphous ethylenic copolymer in a specified amount. CONSTITUTION:(A) A crystalline ethylene.propylene block copolymer having a Q value of 8-50, the Q value being a barometer exhibiting a mol.wt. distribution is compounded with 1-30wt.% of an amorphous ethylenic copolymer comprising amorphous ethylene.butene copolymer or a mixture of 50wt.% of the amorphous ethylene.butene copolymer and <=50wt.% of one kind of more of polymers selected from amorphous ethylene.propylene random copolymer, etc., and, if necessary, <=50wt.% of an inorganic filler to provide a composition having a melt flow index of 1-100g/10min.

Description

[Detailed description of the invention] [Industrial field of application] The present invention has excellent stamping moldability, and is suitable for single-piece resin molding,
The present invention relates to a polypropylene resin for stamping molding suitable for manufacturing two-layer integrally molded products and three-layer integrally molded products.

[Conventional technology]

In recent years, molded products made of thermoplastic resin such as polypropylene are used as base materials for interior parts such as automobile door trims, pillars, and glove boxes, as well as office equipment such as chairs. In order to give a feeling of touch,
The base material is a sheet-like composite material (hereinafter referred to as the surface material) made by laminating a fabric or a fabric material made of a fabric or a skin material such as PVC leather or genuine leather as a surface material and a foam layer made of a synthetic resin. Products are often used by laminating them onto the surface of materials.

Conventionally, the manufacturing method for this type of product is to use a thermoplastic resin molding material to make a molded product in a predetermined shape as a base material using an injection molding method, and then apply an adhesive to the surface of the base material. There is a method of manufacturing the product by manually attaching the skin material of the facing material to the surface along the molded shape of the base material, or a method of manufacturing the product by fixing the facing material in advance to an injection mold. There is a method (referred to as injection insert molding method) in which a molded product having a surface layer on the surface layer is produced by molding using an injection molding method.

However, according to the former method, since high pressure and temperature are not applied to the facing material itself, a desirable product can be obtained with almost no loss of the feel of the facing material, but it requires manual labor. Due to the large amount of
It has become a big standstill of productivity.

In addition, the latter injection insert molding method requires high pressure (usually 300 kg/cj) of the plasticized resin during resin injection.
Due to the effects of the above) and high temperature flow, the foam layer of the covering material that is in direct contact with the resin is crushed or torn, and the necessary cushioning properties are not only lost, but also the covering material side is torn, fallen hair, and wrinkled. However, there is a drawback that the appearance is significantly impaired due to a change in gloss.

In order to solve this problem, moldability is achieved by measuring a certain amount of molten resin from a nozzle or T-die, placing it on a mold with a surface material fixed in advance, and keeping the resin at a low temperature (usually 220°C or less). ), a stamping molding method is known in which molding is performed at low pressure (usually 601 cg/cd or less).

[Problem to be solved by the invention]

However, the stamping bottom shape integrated with the facing material requires a low resin temperature (usually below 220°C) and a low pressure (usually 60°C or less).
(kg/cd or less) (hereinafter referred to as low-temperature, low-pressure molding), the molten resin is placed from a nozzle or T-die onto the mold in a fixed amount and in a fixed shape (hereinafter referred to as charge). In this case, the temperature and viscosity of the molten resin on the mold tend to change. Furthermore, depending on the size and shape of the molded product, it is difficult to maintain the shape of the charged resin because the mold remains open and the molten resin is allowed to cool in the air. As a result, during skin integral molding, the molded product may be partially filled with resin (hereinafter referred to as "short shot"), or the molded product may be partially overfilled with resin, causing it to flow out from the gap in the mold and solidify (hereinafter referred to as "short shot"). ), there are problems with molding stability, such as some resins melting and breaking the skin material.

Moreover, molding residual strain remains in the obtained molded product, and as a result,
There is a problem in that the resulting molded product suffers from post-deformation such as sink marks and warpage.

A material suitable for solving these problems and obtaining stable molded products is not yet known.

The object of the present invention is to provide a surface material that has stable stamping formability, with little change in temperature or viscosity of the molten resin during charging during stamping molding, and no change in shape of the charged molten resin. An object of the present invention is to provide a polypropylene composite resin composition from which a small-layer or multi-layer surface-decorated integrally molded article can be obtained.

[Means to solve the problem]

The present inventors made use of polypropylene, which has various melt viscosity characteristics and excellent heat resistance, and developed a method in which a fixed amount of molten resin is charged onto a mold from a nozzle or T-die in a fixed shape during stamping molding. In order to obtain a polypropylene composite resin composition that has stable stamping moldability due to temperature changes and viscosity changes of the molten resin at the beginning and end of charging, we conducted intensive research.

As a result, crystalline ethylene with a specific molecular weight distribution
A polypropylene composite resin composition in which a specific amount of an amorphous ethylene-based copolymer is blended into a propylene block copolymer, or a polypropylene composite resin in which a specific amount of an inorganic filler is blended into the composition; It was discovered that the temperature change and viscosity change of the molten resin during charging are small, the shape of the charged resin is maintained, and the stamping moldability is excellent, and based on this knowledge, the present invention was completed.

That is, the present invention has a molecular weight distribution of 1 and Qlin, which is an index representing molecular weight distribution, of 8 to 5.
A polypropylene composite resin composition for stamping molding, in which 1 to 30% by weight of an amorphous ethylene-based copolymer is blended with a crystalline ethylene-propylene block copolymer.

2. A crystalline ethylene-propylene block copolymer with a Q value, which is an index representing molecular weight distribution, of 8 to 50 is blended with 1 to 30 weight 1% of an amorphous ethylene Juff 1 polymer and an inorganic filler of 50 weight J196 or less. Polypropylene composite resin composition for stamping molding.

3. The melt flow index (MFR) of the polypropylene composite resin composition for stamping molding is 1.0 or more.
The polypropylene composite resin composition for stamping molding according to any one of the above items 1 and 2, which has a rate of 100 g/10 minutes.

4. The amorphous ethylene copolymer contains 50% by weight or more of an amorphous ethylene-butene copolymer or an ethylene-butene bowl polymer, an amorphous ethylene-propylene random copolymer, or a styrene-butadiene thermoplastic elastomer. , ethylene-vinyl acetate copolymer, high-density polyethylene, low-density polyethylene, and In-chain low-density polyethylene, or a mixture of 50% by weight or less of two or more of the above-mentioned items 1 and 2. Alternatively, the polypropylene composite resin composition for stamping molding according to any one of Item 3.

It is.

The crystalline ethylene-propylene block copolymer used in the present invention is a crystalline ethylene-propylene block copolymer that has a propylene component as its main component and has a Q value, which is an index representing molecular weight distribution, in the range of 8 to 50. , preferably a crystalline ethyl 1/propylene block copolymer having a QifI in the range of 8 to 25, particularly preferably 8 to 15.

If the Q value is less than 8, when the resulting composition is melt-kneaded and the molten resin is charged from the nozzle of the extrusion machine or the T-die to the mold for stamping bottom shape, the nozzle or T-die is charged.
Not only does the diameter, width, or thickness of the molten resin shrink significantly during the process from the lip of the die to the top of the mold (hereinafter referred to as "melt shrinkage"), but the shape of the molten resin charged on the mold changes (hereinafter referred to as "mold shrinkage"). (referred to as upper shrink) is also large, making stamping formability unstable and undesirable. Also, the Q value is 50
If the size is larger, the above-mentioned melt shrinkage and mold shrinkage are good, but the melt kneading tends to be uneven, causing extrusion fluctuations, the metering is unstable when charging the molten resin, and the wall thickness is poor. This is undesirable as it becomes uneven and causes short shots and bursts.

The composition of the crystalline ethylene-propylene block copolymer is not particularly limited, but preferably the propylene homopolymer in the first stage accounts for 70 to 95% by weight of the total polymer, and the ethylene content in the second stage is 50% by weight. ~90% by weight
This is a crystalline ethylene-propylene block copolymer obtained by copolymerizing an ethylene-propylene random copolymer of 5 to 30% by weight of the total polymer. If the ethylene content of the ethylene-propylene copolymer in the second stage of the crystalline ethylene-propylene copolymer is less than 50 ffl% or more than 90% by weight, melt shrinkage becomes large, which is undesirable. Furthermore, it is also undesirable if the second stage ethylene-propylene random copolymer is less than 5ffi% or more than 30vl% of the total polymer because melt shrinkage is large and stamping formability is unstable.

The Qlm is an index representing molecular weight distribution, and is the weight average molecular weight (
M ) and the number average molecule ffi (M) ratio y
n(M/M
), and the larger this value is, the larger the molecule v
n means that the amount distribution is wide, and the Q value of a general polypropylene homopolymer or copolymer is 3 to 7.

The crystalline ethylene-propylene block copolymer having a Q value of 8 to 50 used in the present invention can be produced by the following production method.

1. A reaction product of an organoaluminum compound (diethyl aluminum monochloride, etc.) and an electron donor (diisoamyl ether, etc.) is reacted with titanium tetrachloride. etc.) and an electron acceptor (such as titanium tetrachloride) in combination with an organoaluminum compound (such as diethylaluminum chloride) and an aromatic carboxylic acid ester (such as methylvalate). In a method of continuously producing a homopolymer or a copolymer of monopropylene by polymerizing propylene in the presence of organic matter, (a) three or more polymerization vessels connected in series are used, and (b) a catalyst to be used. (c) The total weight of the catalyst is supplied to the first polymerization vessel to perform homopolymerization of propylene, and the catalyst is sequentially and continuously transferred to the second and subsequent polymerization vessels together with the produced propylene polymer, (c) this second and subsequent polymerization vessels. Ethylene (in the present invention, 50 to 90% by weight) and propylene are supplied to the polymerization vessel of 2 to copolymerize ethylene and propylene; Hydrogen is used as a molecular weight regulator in the polymerization vessel, and the hydrogen concentration in each polymerization vessel is adjusted to decrease sequentially, and (e) the produced ethylene-propylene copolymer is continuously discharged from the final polymerization vessel. , it can be manufactured by

In addition, an example of the conditions in the above manufacturing method is shown below.

(a) Using 3 ffi polymerizers) Polymerization temperature: 72°C for each polymerizer (c) 11 combined pressure crab No. 111 combiner (Re'l); 6 kg/
(J.

2nd ffi combiner (Ro'2); 8 kg/aJ
.

Third polymerization reactor (Re'8); lokg/cd
.

(d) In Examples 1 to 3 of Table 1 below, ethylene and propylene (ethylene content is 60% by weight) are added to the second polymerization vessel.
) and (o) the amount of the ethylene-propylene copolymer polymerized in the 122 reactor was 15% by weight of the total polymer.

(r) Hydrogen concentration (mol% of gas phase) and melt flow rate of the obtained ethylene-propylene copolymer (hereinafter referred to as M
It's called FR. ) and QI! is shown in Table 11.

Table 1 *1: One-stage polymer product The MFR of the crystalline ethylene-propylene copolymer is not particularly limited, but is preferably 0.1 to 100 g/
10 minutes, particularly preferably 2.0 to 70 g/10 minutes.

The amorphous ethylene copolymer used in the present invention is ethylene-
50% by weight or more of butene copolymer or ethylene-butene copolymer, amorphous ethylene propylene random copolymer, styrene-butadiene thermoplastic elastomer, ethylene-vinyl acetate copolymer, high-density polyethylene,
One type selected from the group consisting of low-density polyethylene, orthogonal low-density polyethylene, or 2ft1 or more 5011% by weight
It is a mixture of:

The amorphous ethylene copolymer is not particularly limited, but preferably has a butene content of 1 to 30% by weight and an MFR of 1.
~40 g/10 min of amorphous ethylene-butene copolymer.

The butene content of the amorphous ethylene-butene copolymer is 1
If it is less than 30% by weight, the melt shrinkage and shrinkage on the mold will increase, and if it exceeds 30% by weight, the melting shrinkage will be small and it is considered good, but the shrinkage on the mold will increase and the stamping formability will become unstable, which is not preferable. .

Furthermore, if the VFR is less than lr/10 minutes, not only will melt shrinkage and mold shrinkage increase, but also delamination between resins will occur, making stamping formability unstable, and the resulting molded This is undesirable because it reduces the appearance, rigidity, and impact strength of the product.

Also, if the MFR is greater than 40 g/10 minutes,
Melt shrinkage and shrinkage on the mold become large, making stamping formability unstable, which is undesirable.

The blending amount of the amorphous ethylene copolymer is 1 to 30 ffi% based on the composition. If the blending amount is less than 1% by weight, melt shrinkage and shrinkage on the mold become large, and stamping formability becomes unstable, which is not preferable.

Moreover, if the blending amount exceeds 30% by weight, melt shrinkage will be small and good, but shrinkage on the mold will increase and stamping formability will become unstable, which is not preferable.

To the amorphous ethylene system of the present invention, 50% by weight or more of the amorphous ethylene-butene copolymer which is a polymer
Amorphous ethylene propylene random copolymer, styrene-butadiene thermoplastic elastomer, ethylene-vinyl acetate copolymer, high-density polyethylene, low-density polyethylene, linear low-density polyethylene or these 2F1 mixed in the following proportions: The above mixtures cannot be particularly limited, but if they are blended in an amount exceeding 50% by weight, ε
This not only increases melt shrinkage and shrinkage on the mold, but also causes delamination between resin layers, making stamping formability unstable, as well as reducing the appearance, rigidity, and impact strength of the resulting molded product. Undesirable.

In the polypropylene composite resin composition for stamping molding of the present invention, up to 50 f of an inorganic filler is added to the composition.
It is possible to mix up to fl amount%.

Examples of the inorganic filler include talc, calcium carbonate,
mica, glass fiber, calcium sulfate, clay,
Examples include asbestos, and talc, calcium carbonate, mica, or a mixture thereof is preferred in view of melt shrinkage, mold shrinkage, surface characteristics, appearance, rigidity, heat resistance, impact resistance, etc. of the resulting molded product.

If more than 50% by weight of the inorganic filler is mixed, shrinkage on the mold increases during stamping and stamping properties become unstable, which is not preferable.

The stamping molding method is a molding method in which thermoplastic resin is heated above its melting point, melted, cross-wired, and measured, then charged onto an open stamping mold, and then shaped by closing the mold and applying pressure. It's a method.

As a method for charging the molten resin onto the mold, an extruder, blow molding machine, injection molding machine, etc. can be used.

Corresponding to these charging methods, the polypropylene composite resin composition for stamping molding of the present invention needs to have an MFR in the range of 0.1 to 100 g/10 minutes,
If the VFR is less than O, Ig/10 minutes, not only will shrinkage on the mold become large and stamping formability will deteriorate, but also the resulting molded product will have a poor appearance, which is undesirable. Moreover, if the MFR is larger than 100 g/10 minutes, melt shrinkage and mold shrinkage will increase, and stamping formability will deteriorate, which is not preferable.

The composition of the present invention contains various additives normally added to polypropylene compositions, such as antioxidants, antistatic agents, ultraviolet absorbers, lubricants, metal deactivators, pigments, dispersants, and neutralizing agents. It can be added within a range that does not impair the effects of the invention.

The composition of the present invention comprises the above-mentioned crystalline ethylene-propylene block copolymer, amorphous ethylene-based copolymer or crystalline ethylene-propylene block copolymer, amorphous ethylene-based copolymer and an inorganic filler. Alternatively, it can be obtained by mixing predetermined amounts of each of the above-mentioned various additives using a stirring mixer, and melting and blending the mixture using various melt mixers to form pellets.

As the stirring and mixing device, for example, a Hensel mixer (trade name), a super mixer, etc. may be used, and as the melt-kneading device, a roll, a panburi mixer, an extruder, etc. may be used.

Melting mixture again! The temperature is 180°C to 300°C, preferably 200°C to 250°C.

To manufacture stamping molded products, use an extruder, blow molding machine, injection molding machine, etc. to heat the composition of the present invention above its melting point, melt it, cross-wire it, measure it, and place it on an open lower mold. By discharging, dispersing or placing, closing the mold and applying pressure to shape, a molded product with a beautiful appearance and stable moldability can be obtained.

In addition, by automatically or manually setting the facing material on top of the molten resin or into the upper mold before the mold is closed, and then stamping the bottom, we are able to produce decorative molded products with beautiful two-layered surfaces. It is possible to obtain an integrally decorated bottom-shaped product with three or more layers with a cushion layer attached.

The covering material includes PVC leather, paper, woven fabric, non-woven fabric, or a mixture thereof;
As a cushion layer, polypropylene, polyethylene,
1.5 to 70 times more foaming or basis weight than polyurethane! Use 1 to 200 g of polypropylene or polyester nonwoven fabric or a combination thereof.

The composition of the present invention can also be used in other molding methods such as injection molding, sheet molding, sheet press bottom molding, etc.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples.

The invention is not equally limited by this example.

In the following Examples and Comparative Examples, the test methods used for various evaluations are as follows.

(1) MFR JIS K-6758, 230℃ (2) Qll By gel permeation chromatography.

(3) The necking rate of the molten resin was constant at 11-1 when it was extruded at a resin temperature of 200°C from a charge nozzle die with a melt shrinkage width of 150 m5 and a thickness of 2 m-, and allowed to fall freely for 1 m at 300°C.

(4) Shrink on mold A molten resin extruded from a charge nozzle die with a width of 150 mm and a thickness of 2 rounds at a resin temperature of 200°C and a length of 300 mm is made into a mold with a width of 200 mm, a length of 350 mm, and a depth of 4 mm. C) A charge nozzle was moved parallel to the length direction of the mold onto the lower mold of the +- flat plate mold to charge the resin, and the area change rate was measured 60 seconds after the end of charging. The n5 mold surface temperature was adjusted to a constant value of 50° C. for both the upper and lower molds using hot water.

If the area change rate is less than 90%, the assimilation rate of the resin is fast and a rapid volume change is occurring. Moreover, when it becomes larger than 110%, it means that the melt viscosity of the resin is small and it spreads on the mold.

(5> Stamping molding state - 1 300 mm long molten resin extruded from a charge nozzle die with a length of 150 m and a thickness of 2 am at a resin temperature of 200°C to a width of 200 mm, a length of 350 mm and a depth of 4.0 mm. The charge nozzle was moved parallel to the length direction of the mold to charge the molten resin onto the lower mold for flat plate molding, and 60 seconds after charging was completed, the upper and lower molds were closed and the thickness was increased using a clamping pressure of 40 kg/cJ. 1. Check the short shot and paris condition when forming an 8-open flat plate.

At this time, the mold surface temperature was adjusted to be constant at 50° C. for both the upper and lower molds using hot water.

(6) Stamping molding state-2 The facing material is set in the upper mold of the flat plate molding mold, and the width is 15 mm.
Resin temperature 2 from charge nozzle die with 0 axis thickness 21m1
A molten resin extruded at 00°C with a length of 300 am and a width of 20
0n+, the charging nozzle is moved parallel to the length direction of the mold onto the lower mold of the flat plate molding mold having a length of 350 mm and a depth of 4.0 + 1 m to charge the molten resin, and charging is completed 6.
After 0 seconds, close the upper and lower molds and apply a clamping pressure of 40 kg/c-.
Resin thickness: 1.8sm, total thickness with surface material: 3.8m
Check the condition of short smudges and cracks during molding of the flat plate of size 2.3, and the surface condition of the facing material side.

At this time, the mold surface temperature was set at 20℃ for the upper mold using hot water.
Lower mold constant at 50℃ M! ! did.

For the covering material ε, the cushion layer is foamed 25 times as much as PP (
Made by Toshi ■: Product name Befu), the outer skin is PvC leather (made by Kyowa Leather) and the basis weight is heavy fA 20 SR p.
P nonwoven fabric was used.

(7) Appearance Stamping molding mentioned above! ! ! -1 and the surface condition of the molded products obtained by stamping molding B-2.

In stamping molding state-1, uneven gloss on the surface of the molded product, etc.

Stamping molding! ! ! -2, confirm the shadow on the facing material side.

0: Beautiful ×: Uneven gloss, cushion layer of the covering material, discoloration, tearing, and change in gloss of the covering material.

Moreover, each component used is as follows.

PP: Polypropylene block: Crystalline ethylene-propylene block copolymer, Homo: Propylene T11 monopolymer Random: Crystalline ethylene-propylene random copolymer EBM: Polymer to amorphous ethylene-butene Talc: Manufactured by Linhua Co., Ltd. Particle size: 2-5μ TC: Calcium carbonate manufactured by Linhua Co., Ltd., particle size: 2-5μ Mica: manufactured by Repco, particle size: 2-5μ EP: Non-Eb ethylene propylene random copolymer MFR (230°C): 7g/10 Min., ethylene content f180% by weight, product name: Mitsui Petrochemical ■
Tafmer PO6 0 SBR: Styrene-butadiene thermoplastic elastomer MFR (190°C): 3. /10 minutes, FF140FF containing styrene! Amount %, Product name: Japan Synthetic Rubber Co., Ltd. RT2000 EVA: Ethylene-vinyl acetate copolymer MFR (190°C): 1. 5+r/10 minutes, vinyl acetate content ff120% by weight Product name: Ultrasen 31 manufactured by Tosoh ■ LDPE: Low density polyethylene MFR (190°C): 2'3 g/10 minutes, ethylene homopolymer Product name: Vetrocene 08 manufactured by Tosoh ■ HDPEs high density polyethylene MFR (190°C): 5g/10 min, ethylene homopolymer Product name: Chisso made by Chisso Polyethylene M850 L-LDPE: Linear low density polyethylene MFR (19
0°C): 20 g/10 min, ethylene homopolymer Product name: Tosoh Niboron-L 70 Examples 1 to 38, Comparative Examples 1 to 22 m2 to 7 Each component shown in the table was mixed using a high-speed stirring hand mixer ( The mixture was mixed for 3 minutes at room temperature using a Henschel mixer (trade name), and the mixture was granulated using an extrusion granulator with a screw diameter of 40 mm. Next, these granules are processed by Nakatani Machine ■IJNV
Molded with a stamping molding machine using a C-65 type extruder, melted and shrunk, shrinked on the mold, and stamped! -1. Stamping molding! -2 evaluation,
The results are shown in Tables 2-7.

Examples 1 to 38 in Tables 2 to 5 and Comparative Examples 1 to 3 in Tables 6 to 7
Comparing No. 22, the composite resin compositions for stamping molding of Examples 1 to 38 are compositions that can provide molded products with excellent molding stability and appearance in the stamping bottom shape.

〔Effect of the invention〕

In the stamping molded product using the composite resin composition of the present invention, in integral multilayer stamping molding with a single layer stamping bottom shape made of the resin composition itself and a decorative surface material,
Because it has stable moldability and the surface of the obtained molded product is beautiful, it is suitable for automobile interior parts (door panels, seat packs, etc.), office equipment (chairs, etc.), outer panels of home appliances, etc. It can be used for.

Furthermore, by using a metal foil or the like having electrical conductivity instead of the covering material, the resin composition can also provide a molded product with excellent electromagnetic wave shielding performance.

Therefore, the composite resin composition for stamping molding of the present invention is extremely useful as a material for molding single-layer and multi-layer structures such as interior parts such as automobile door panels, pillar seat packs, and office equipment such as chairs by the stamping molding method. It is.

Claims (1)

[Claims] 1. Stamping in which 1 to 30% by weight of an amorphous ethylene copolymer is blended with a crystalline ethylene-propylene block copolymer having a Q value, which is an index representing molecular weight distribution, of 8 to 50. Polypropylene composite resin composition for molding. 2. Blending 1 to 30% by weight of an amorphous ethylene copolymer and 50% by weight or less of an inorganic filler to a crystalline ethylene-propylene block copolymer whose Q value, which is an index representing molecular weight distribution, is 8 to 50. Polypropylene composite resin composition for stamping molding. 3. The melt flow index (MFR) of the polypropylene composite resin composition for stamping molding is 1.0 to 10.
3. The polypropylene composite resin composition for stamping molding according to claim 1, wherein the polypropylene composite resin composition is 0 g/10 minutes. 4. The amorphous ethylene copolymer is an amorphous ethylene-butene copolymer or an ethylene-butene copolymer at 50% by weight.
The above, an amorphous ethylene propylene random copolymer,
Claims that the product is a mixture of one or more selected from the group consisting of styrene-butadiene thermoplastic elastomer, ethylene-vinyl acetate copolymer, high-density polyethylene, low-density polyethylene, and linear low-density polyethylene at 50% by weight or less The polypropylene composite resin composition for stamping molding according to any one of claim 1, claim 2, and claim 3.