JPH0819294B2 - Composite resin composition, composite resin composition for sheet molding and molded article thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite resin composition, a composite resin composition for forming a sheet and a molded article thereof, and more specifically, it has biodegradability and photodegradability and is excellent in mechanical properties. A composite resin composition suitable for molding into various molded products, a composite resin composition for sheet molding suitable for sheet molded products among various molded products, and a photo-decomposable product which is preferably manufactured from these, The present invention relates to a molded article having biodegradability and excellent mechanical properties.

[0002]

2. Description of the Related Art Plastics have enriched people's lives by making them tough, lightweight, beautiful, inexpensive, stable and available in large quantities.

However, in recent years, when such plastics have been mass-produced, their chemical stability has become rather problematic.

That is, as the interest in the global environment as a whole has increased in recent years, it has become a problem how to incorporate the plastic that has finished its role into the natural material cycle.
Plastics that have completed their role are those that can be incorporated into the earth's material cycle (carbon cycle) by being assimilated and decomposed by microorganisms that normally exist in the ground and water in the natural environment. Development is expected.

Under these expectations, at present, for example, a composite film obtained by mixing finely divided cellulose and an aqueous solution of chitosan salt, casting the mixture on a flat plate and drying it (see Material ”p27, Vol3
9, No8), a sheet obtained by adding a polyol as a hydrophilic plasticizer to gluten powder, roll-kneading at about 30 ° C., and press-molding the masticated product after drying (“industrial material” p31, Vol39, No8), Glycolide or glycolide-lactide copolymer (“industrial material” p34, Vol39, No8), which is biodegradable in itself, has been proposed.

However, such a biodegradable plastic is poor in practical use in that the material is limited and it does not impart biodegradability to a general-purpose plastic such as polyolefin.

An invention in which a general-purpose plastic such as polyolefin is provided with biodegradability is proposed in Japanese Patent Laid-Open No. 4-356538.

The invention described in this publication is a biodegradation containing 30 to 80% by weight of a powder of a natural fibrin substance.
A sexual foamed polyolefin-based resin molded article. And
In the column of "Detailed Description of the Invention", as the polyolefin resin, low density polyethylene, high density polyethylene,
Only polyethylene-based resin such as ethylene-vinyl acetate copolymer, polypropylene, propylene copolymer, etc. are exemplified, and it is also clarified concretely by referring to the column of “Example”. Is an ethylene-vinyl acetate copolymer resin only.

Therefore, it is not clear whether the general-purpose plastics other than the ethylene-vinyl acetate copolymer resin have the biodegradability claimed in the publication, only by the description of the publication.

As described above, under the recent increase in the protection of the global environment, it is possible to protect the earth by biodegrading or photodegrading it after using it while providing it with mechanical properties sufficient to endure practical use. There is a strong need for a general-purpose plastic composition that can be incorporated into the material cycle.

The present invention has been completed based on the above circumstances.

That is, an object of the present invention is that it is excellent in biodegradability and photodegradability and has mechanical properties that can withstand practical use, and is suitable for processing into various molded articles, especially sheet molded articles. It is to provide a composite resin composition.

Another object of the present invention is to perform molding by various molding techniques such as vacuum molding, blow molding, press molding, extrusion molding and injection molding.
It is an object of the present invention to provide a composite resin composition which can form a beautiful molded product having no bubbles on the surface.

[0014]

The invention according to claim 1 for solving the above-mentioned problems has a melt index of 1.
5 to 4 g / 10 min Polypropylene and melt index is that Ri polypropylene Tona is 0.2 to 1.0 g / 10 min, a melt index of 1.5 to 4 g /
Melt index for polypropylene that is 10 minutes
Polypropylene with a weight of 0.2-1.0 g / 10 minutes
A polypropylene component 90-50 wt% ing 1-2 are contained in a proportion of times by weight, and wood flour 10-50 wt% having a particle size of 30 to 100 [mu] m, the total weight of the polypropylene component and wood flour to 3. The invention according to claim 2 , wherein the composite resin composition comprises a modified polyolefin contained in an amount of 0.5 to 3% by weight.
Has a melt index of 1.5 to 4 g / 10 min.
Polypropylene and melt index 0.2-
Made from polypropylene that is 1.0 g / 10 min
Polypro with index of 1.5 to 4g / 10 minutes
Melt index for pyrene is 0.2-1.0g
10 to 10 minutes of polypropylene is 1 to 2 times by weight
Polypropylene component contained 90 to 50% by weight
With a melt index of 0.1-0.5 g / 10 minutes
Some high density polyethylene and melt index 1
Made from linear low density polyethylene that is ~ 3 g / 10 min
Polyethylene component 20 to 40% by weight and 30 to 100
10 to 50% by weight of wood flour having a particle size of μm,
Propylene component, polyethylene component and wood flour
The change in the content of 0.5 to 3% by weight based on the total weight.
Composite resin characterized by having an organic polyolefin
The composition according to claim 3 is a melt index
High-density poly-ene with a coat of 0.1-0.5 g / 10 minutes
Melt index is 1 to 3 g / 10 min.
The amount of linear low-density polyethylene is 1 to 1.5
The composite resin composition according to claim 2, wherein the composite resin composition has a weight ratio.
Ri, the invention according to claim 4, wherein the preceding claims noise
A composite resin composition described in any one of
A composite resin composition for forming a sheet, which is formed by the method according to claim 5.
Ming is the composite resin set according to any one of claims 1 to 3.
A molded article characterized in that it is obtained from adult product, wherein
The invention according to claim 6 is the sheet molding according to claim 4.
Molded article obtained from a composite resin composition for automobiles
It is.

The structure of the present invention will be described in detail below.

One aspect of the present invention is to provide a first composite resin composition obtained by mixing a polypropylene component composed of two specific types of polypropylene, wood flour having a specific particle size, and modified polypropylene in a specific ratio. A second composite resin composition obtained by blending a polypropylene component composed of two types of polypropylene, a polyethylene component composed of two specific types of polyethylene, wood flour having a specific particle size, and a modified polypropylene in a specific ratio. Regarding

It should be noted in the present invention that, when the specific conditions described below are satisfied, general-purpose plastics such as polypropylene are given biodegradability and photodegradability, and their mechanical properties are not deteriorated. That is, it can be sufficiently applied to the use of conventional general-purpose plastics. As in the present invention, it has not yet been scientifically elucidated as to why a specific polypropylene or polyethylene is selected and a specific component is combined to have biodegradability and photodegradability. The composite resin composition of the present invention having both biodegradability and biodegradability is unexpected. Interestingly, when the composite resin composition of the present invention is used to form a sheet molded article, the above-mentioned biodegradability and photodegradability are better expressed. When a thick molded product or a lump-shaped molded product is obtained using the composite resin composition of the present invention, the expression of biodegradability and photodegradability decreases.

The polypropylene component used in the composite resin composition according to the present invention has a melt index (hereinafter sometimes abbreviated as MI) of 1.5 to 4 g /.
Polypropylene P for 10 minutes, preferably 1.5-3
P ₁ and melt index of 0.2 to 1.0 g / 1
It consists of polypropylene PP ₂ at 0 minutes, preferably 0.3-0.7 g / 10 minutes.

When the polypropylene PP ₁ and polypropylene PP ₂ each have a melt index within the above range, not only the mechanical properties of the composite resin composition, such as elongation, rigidity, tensile strength, and tear strength, can be sufficiently endured for practical use. , Photodegradability and biodegradability are improved. If the melt index of the polypropylene PP ₁ is below the above range, the mechanical strength will be poor, and conversely, if the melt index is above the range, the sheet processability will be extremely poor. Further, when the melt index value of polypropylene PP ₁ is within the range specified by the present invention but the melt index value of polypropylene PP ₂ is outside the range specified by the present invention, or vice versa, the same processing is performed. Property, particularly sheet workability, becomes poor, and mechanical properties deteriorate.

In the composite resin composition of the present invention, polypropylene PP having the above specific Merck index
Polypropylene PP ₂ is blended in a proportion of 1 to 2 times by weight _1.

Melt index is 1.5 to 4 g / 10
The composite resin composition in which the polypropylene having the melt index of 0.2 to 1.0 g / 10 min is blended with the polypropylene having the above proportion in the above-mentioned ratio has good sheet processability, its mechanical properties, Biodegradability and photodegradability are particularly improved.

In the composite resin composition of the present invention, as the polypropylene PP ₁ and polypropylene PP ₂ having the above-mentioned properties, for example, propylene homopolymer, copolymer of propylene and other olefin, etc. are appropriately selected and used. Can be done. Examples of the copolymer of propylene and other olefins include block copolymers containing ethylene or butene, and random copolymers.

The polyethylene component used in the composite resin composition of the present invention has a melt index of 0.1 to 0.
5 g / 10 min, preferably 0.2 to 0.4 g / 10 min high density polyethylene (hereinafter sometimes abbreviated as HDPE) and melt index 1 to 3 g
/ 10 minutes, preferably 1.5 to 2 g / 10 minutes of linear low-density polyethylene (hereinafter sometimes abbreviated as LLDPE).

When the melt index of the high-density polyethylene is within the above range, the object of the present invention can be achieved well, biodegradability and photodegradability can be imparted to the composite resin composition, and the composite resin composition can be obtained. It does not deteriorate the mechanical properties of the resin composition. When the melt index of the high-density polyethylene is out of the above range, the moldability of the composite resin composition is lowered, and even if a molded product is obtained, the mechanical properties are significantly lowered. In addition, biodegradability and photodegradability are also reduced.

When the melt index of the linear low-density polyethylene is within the above range, a composite resin composition capable of producing a molded article having excellent mechanical properties can be obtained, and further, biodegradability and light resistance can be obtained. Excellent in degradability. vice versa,
If the melt index of the linear low-density polyethylene is out of the above range, the sheet processability is poor and the object of the present invention cannot be achieved.

In the present invention, the blending amount of the linear low-density polyethylene having a melt index of 1 to 3 g / 10 min with respect to the high density polyethylene having a melt index of 0.1 to 0.5 g / 10 min is , 1 to 1.5 times by weight .

The wood powder used in the present invention has a particle size of 30 to 100 μm, preferably 40 to 80 μm. When the particle size of the wood powder is within the above range, the dispersibility of the wood powder in the composite resin composition becomes good, and the composite resin composition having good mechanical properties and excellent biodegradability is obtained. be able to. When the particle size of the wood powder is less than the above range, the dispersibility of the wood powder in the composite resin composition is rather deteriorated, and the mechanical properties of the molded product obtained by molding the composite resin composition can withstand practical use. If the particle size of the wood powder exceeds the above range, the sheet processability is deteriorated and the appearance of the molded product is remarkably deteriorated.

There are no particular restrictions on the type of wood flour as long as the particle size is within the above range, and wood flour from various woods can be used.

As the modified polyolefin, those obtained by chemically modifying polyolefin with liquid rubber and / or unsaturated carboxylic acid (including anhydride) or its derivative are preferably used. Here, as the liquid rubber, terminal hydroxylated polybutadiene is preferable. In the production of this chemically modified polyolefin, the polyolefin, liquid rubber and / or unsaturated carboxylic acid or its derivative are reacted with a radical generator such as benzoyl in a solvent such as xylene, toluene, heptane or monochlorobenzene. Good. Details of the method for producing the chemically modified polyolefin are disclosed in JP-A-54-124049.

Among the modified polyolefins, modified polypropylene is preferred. The modified polypropylene is one obtained by chemically modifying polypropylene with liquid rubber and / or unsaturated carboxylic acid (including anhydride) or its derivative. Examples of the liquid rubber include terminal hydroxylated polybutadiene. Examples of the unsaturated carboxylic acid include maleic anhydride, acrylic acid, methacrylic acid and their esters.

The ratio of each component in the first composite resin composition of the present invention is such that the melt index is 1.5 to the total of polypropylene component and wood flour.
The proportion of polypropylene component consisting of polypropylene PP ₁ having a flow rate of 4 g / 10 minutes and polypropylene PP ₂ having a melt index of 0.2 to 1.0 g / 10 minutes is 9
0 to 50% by weight, preferably 80 to 60% by weight,
The ratio of wood flour having a particle size of 30 to 100 μm is 10 to 5
It is 0% by weight, preferably 20 to 40% by weight. Also,
The blending ratio of the modified polyolefin is 0.5 to 3% by weight based on the total weight of the polypropylene component and wood flour.
It is preferably 0.8 to 2% by weight.

When the blending ratio of the polypropylene component is within the above range, the mechanical properties are maintained to such an extent that there is no practical problem. Further, when the blending amount of wood powder is within the above range, both the biodegradability and photodegradability of the composite resin composition are well expressed. Further, when the modified polypropylene is contained in the blending ratio within the above range, the sheet processability is good,
It has excellent mechanical properties and, combined with the presence of wood flour, improves biodegradability and photodegradability. Although the reason is not clear, it is presumed that the wood flour having a hydrophilic group such as a hydroxyl group and an ester group and the modifying group in the modified polyolefin work together to promote photodegradability and biodegradability.

Regarding the ratio of each component in the second composite resin composition of the present invention, polypropylene PP having a melt index of 1.5 to 4 g / 10 min with respect to the total of polypropylene component, polyethylene component and wood flour. ₁ and a melt index of 0.2 to 1.0 g /
The proportion of polypropylene component consisting of polypropylene PP ₂ which is 10 minutes is 30 to 50% by weight, preferably 35 to 50% by weight.
45 wt% and a melt index of 0.1 to 0.
The proportion of the polyethylene component consisting of high density polyethylene of 5 g / 10 minutes and linear low density polyethylene having a melt index of 1 to 3 g / 10 minutes is 20 to 40.
% By weight, preferably 25-35% by weight, 30-1
The proportion of wood flour having a particle size of 00 μm is 10 to 50% by weight, preferably 20 to 40% by weight. The blending ratio of the modified polyolefin is the polypropylene component,
0.5 based on the total weight of polyethylene component and wood flour
-3% by weight, preferably 0.8-2% by weight.

When the polyethylene component is contained in the ratio within the above range, even if the content of the polypropylene component is less than that in the first composite resin composition, the mechanical properties of the obtained composite resin composition are It is possible to obtain a molded article which is practically satisfactory without any decrease.

The composite resin composition of the present invention may contain other components such as pigments, colorants, antioxidants, etc. within the range that does not impair the object of the present invention.

The composite resin composition of the present invention can be produced by mixing or kneading the polypropylene component, the polyethylene component in the second composite resin composition, the wood powder and the modified polyolefin by a known method. In order to produce the composite resin composition, the above components may be mixed or kneaded at one time, but it is preferable to adopt a masterbatch method for mixing or kneading.

The obtained composite resin composition is subjected to various molding methods such as injection molding, extrusion molding, T-die molding, blow molding, vacuum molding and press molding after being pelletized. It can be processed into molded products.

This composite resin composition is suitable for use as a molded sheet, and in this case also, a pellet is usually formed into a sheet by a molding means such as T-die extrusion molding, press molding, calender molding, and a vacuum molding machine. It can be molded into a sheet molded product by a molding machine such as a press molding machine.

Molded articles obtained by using the composite resin composition of the present invention, especially sheet molded articles or thin molded articles,
Since it has photodegradability and biodegradability by itself and is excellent in mechanical properties, it is extremely suitable for both practical use and environmental problems.

[0040]

[Effect] The composite resin composition of the present invention and the composite resin composition for sheet molding have biodegradability and photodegradability, and in spite of the addition of wood flour, mechanical properties are practically acceptable. It is maintained or improved to some extent. In addition, the molded article obtained from this composite resin composition, particularly the sheet molded article, has no bubbles and the like that often occur during the molding process, and the surface of the molded article, particularly the sheet molded article, has a tactile sensation peculiar to plastics. However, it has a soft feel, has a paper-like feel when the molded product is thin, and has a woody feel when the molded product is thick. Further, it is possible to manufacture a sheet molded product having a beautiful appearance with almost no foaming or flash marks.

[0041]

EXAMPLES (Examples 1 to 24, Comparative Examples 1 to 24) The following polypropylene, optionally polyethylene, wood flour, and the above modified polypropylene were blended at the blending ratios shown in Tables 1 and 3, and the blended The product was kneaded with a Banbury mixer at 200 ° C. for 15 minutes and then pelletized.

Using the pellets, a test piece having a thickness of 0.5 mm was prepared by extrusion molding, and its mechanical properties, photodegradability and biodegradability were evaluated. The results are shown in Tables 2 and 3.

-Components-Polypropylene component Polypropylene PP ₁ PP (1); MI = 1.5 g / 10 min, Idemitsu Petrochemical Co., Ltd. E-200G PP (2); MI = 2.5 g / 10 min, Idemitsu Petrochemical Co., Ltd., E-203G polypropylene PP ₂ PP (3); MI = 0.6 g / 10 min, Idemitsu Petrochemical Co., Ltd., E-100G PP (4); MI = 0.9 g / 10 min, Idemitsu Petrochemical Co., Ltd., E-250G polypropylene PP (5); MI = 10 g / 10 min, Idemitsu Petrochemical Co., Ltd., J-762H Polyethylene component HDPE (1); MI = 0.2 g / 10 min, Idemitsu Petrochemical Co., Ltd., 520E HDPE (2); MI = 0.4 g / 10 min, Idemitsu Petrochemical Co., Ltd., 530M LLDPE (1); MI = 1.0 g / 10 min, Idemitsu Petrochemical Co., Ltd. 0138N LLDPE (2); MI = 2 g / 10 minutes, manufactured by Idemitsu Petrochemical Co., Ltd., 0238N PE; MI = 1 g / 10 minutes, Idemitsu Petrochemical Co., Ltd. , 440M Wood powder Wood powder (1); Particle size; 45 μm Wood powder (2); Particle size; 70 μm Wood powder (3); Particle size; 200 μm Modified polypropylene modified PP (1); Maleic anhydride modified polypropylene Idemitsu Petrochemical H-1100P modified PP (2) manufactured by Co., Ltd .; acrylic acid modified polypropylene Dexon XPA-2 -Evaluation-Biodegradability evaluation method A test piece was cut out from a sheet molded product, and an aerobic activated sludge tank and an anaerobic activated sludge tank were used. Tensile breaking elongation was measured after immersion in 80 days.

◎ ・ ・ ・ Tensile breaking elongation is reduced by 50% or more ○ ・ ・ ・ Tensile breaking elongation is reduced by 30 to 50% ▲ ・ ・ ・ Tensile breaking elongation is decreased by 30% or less (Elongation over time) / (initial elongation)] × 100}.

Evaluation Method of Photodegradability Using a sunshine weatherometer (Suga tester),
The tensile elongation at break was measured after 500 hours of irradiation time at a panel temperature of 60 ° C.

◎ ・ ・ ・ Tensile breaking elongation decreased by 50% or more ○ ・ ・ ・ Tensile breaking elongation decreased by 30 to 50% ▲ ・ ・ ・ Tensile breaking elongation decreased by 30% or less Mechanical property evaluation method Tensile strength; According to JIS K-6734. Unit: kg / cm ² Tensile elastic modulus: According to JIS K-6734. Unit: kg / cm ² Tensile elongation rate: According to JIS K-6734. Unit:% Tear strength: According to JIS K-8118. Unit: kg / cm Olsen rigidity: According to ASTM D-747. Unit: kg / cm ² Evaluation of appearance ◎ ・ ・ ・ Soft feeling, no flash, no flow mark ○ ・ ・ ・ Soft feeling, some flash mark, flow mark ▲ ・ ・ ・ No soft feeling, flash , There is a flow mark.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

[Table 3]

[0050]

[Table 4]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location C08L 97:02 23:26 23:06) 23:10 (56) Reference JP-A-3-2241 (JP, A) JP 64-51451 (JP, A) JP 63-33440 (JP, A) JP 63-230750 (JP, A) JP 57-180648 (JP, A) Kaisho 57-115437 (JP, A)

Claims (6)

[Claims] 1. A melt index of 1.5 to 4 g / 1.
It consists of polypropylene having 0 minutes and polypropylene having a melt index of 0.2 to 1.0 g / 10 minutes.
The melt index is 1.5 to 4 g / 10 minutes.
Melt index is 0.2 to polypropylene
1 to 2 times the weight of polypropylene that is 1.0 g / 10 minutes
Polypropylene component ing is contained in a proportion of 90 to 50
10% by weight and wood flour having a particle size of 30-100 μm
A composite resin composition comprising 50% by weight and a modified polyolefin contained in a proportion of 0.5 to 3% by weight based on the total weight of the polypropylene component and wood flour. 2. A melt index of 1.5 to 4 g / 1.
It consists of polypropylene having 0 minutes and polypropylene having a melt index of 0.2 to 1.0 g / 10 minutes.
The melt index is 1.5 to 4 g / 10 minutes.
Melt index is 0.2 to polypropylene
1 to 2 times the weight of polypropylene that is 1.0 g / 10 minutes
Polypropylene component ing is contained in a proportion of 90 to 50
% By weight and melt index 0.1-0.5 g / 1
20 to 40% by weight of a polyethylene component consisting of a high-density polyethylene of 0 minutes and a linear low-density polyethylene having a melt index of 1 to 3 g / 10 minutes;
Having 10 to 50 % by weight of wood flour having a particle size of 100 μm, and a modified polyolefin contained in a proportion of 0.5 to 3% by weight based on the total weight of the polypropylene component, the polyethylene component and the wood flour. A composite resin composition comprising: 3. The melt index is 0.1 to 0.5 g.
The blending amount of the linear low-density polyethylene having a melt index of 1 to 3 g / 10 minutes is 1 to 1.5 times the weight of the high density polyethylene of 10 minutes.
7. The composite resin composition according to. 4. A composite resin composition for forming a sheet, which is the composite resin composition according to claim 1. 5. A molded article obtained from the composite resin composition according to any one of claims 1 to 3. 6. A molded article obtained from the composite resin composition for sheet molding according to claim 4.