JP2006002052A - Composite resin composition and molded body thereof - Google Patents

Abstract

A composite resin composition comprising a polyolefin and a plant-based filler is provided, the composite resin composition having improved mechanical strength and water resistance.
SOLUTION: Component (A): plant filler, component (B): polyolefin, component (C): MFR measured under conditions of 180 ° C. and 21.2 N load is in the range of 4 to 700 g / 10 min. And a modified polyolefin in which the graft addition rate of the monomer having an acid group or an acid anhydride group is in the range of 0.10 to 5.0% by weight, and the ratio of the components (A) :( B) is 40 to 90%. % By weight: 10 to 60% by weight (however, the total of both components is 100% by weight), and the ratio of the component (C) when the total of the components (A) and (B) is 100 parts by weight It is in the range of parts by weight.
[Selection figure] None

Description

  The present invention relates to a composite resin composition and a molded body thereof, and more particularly, to a composite resin composition and a molded body obtained by blending a polyolefin with a plant filler, and more specifically, excellent in mechanical strength and water resistance, and plant. The present invention relates to a molded body having an appearance of a system filler material system.

  In recent years, the importance of resource-recycling social systems that reduce industrial waste and reduce environmental pollution has been recognized, and it is important to reuse large amounts of plant-based industrial waste such as wood flour and paper dust. It has become a challenge. On the other hand, polyolefin has excellent physical properties and can be molded in various ways, so it is used in many applications. However, it has a drawback that its rigidity is insufficient. Therefore, in order to solve such drawbacks, attempts have been made to blend plant-based industrial waste with polyolefins. However, plant-based fillers such as wood flour and polyolefin do not have sufficient affinity, and a simple composite resin composition with low rigidity and water resistance is obtained.

  In order to improve the above problems, the addition of various affinity materials has been proposed. For example, rosin-based substances and petroleum resins (Patent Document 1), monomers having acid groups or acid anhydride groups and olefin copolymers ( Patent Document 2), graft-modified polyolefin using a monomer having an acid group or an acid anhydride group (Patent Document 3), a low-molecular modified polyolefin having a number average molecular weight of 3000 to 18000 (Patent Document 4), and the like have been proposed.

JP 58-56534 A JP-A-11-140260 JP-A 63-230750 Japanese Patent No. 3032884

  However, composite resin compositions obtained by blending plant fillers with polyolefins are expected to be used for various parts for construction and various industrial parts, but composite resin compositions using conventional affinity materials are The mechanical strength and water resistance required for these applications are not necessarily sufficient.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a composite resin composition having improved mechanical strength and water resistance, and a molded body thereof.

  As a result of intensive studies, the inventors of the present invention use a graft-modified polyolefin based on a monomer having an acid group or an acid anhydride group and having an MFR and an acid amount (graft addition rate) within a specific range. As a result, the inventors have obtained knowledge that the above object can be easily achieved, and have completed the present invention.

  That is, the first gist of the present invention is that component (A): plant filler, component (B): polyolefin, component (C): MFR measured at 180 ° C. and 21.2 N load is 4 to 700 g. / 10 minutes, comprising a modified polyolefin in which the graft addition rate of the monomer having an acid group or an acid anhydride group is in the range of 0.10 to 5.0% by weight, and component (A): (B ) Is 40 to 90% by weight: 10 to 60% by weight (however, the total of both components is 100% by weight), and the component (C) when the total of components (A) and (B) is 100 parts by weight ) In the range of 1 to 15 parts by weight.

  The second gist of the present invention resides in a molded article characterized by comprising the above composite resin composition.

  According to the present invention, a composite resin composition having improved mechanical strength and water resistance and a molded body thereof are provided.

  Hereinafter, the present invention will be described in detail. First, the composite resin composition of the present invention will be described. The composite resin composition of the present invention contains the following components (A) to (C) as essential components and component (D) as an optional component.

  Component (A) is a plant-based filler, and specific examples thereof include pulp, paper, plywood, MDF (medium fiberboard), bamboo, and the like. Cutting scraps, abrasive scraps, sawdust, pulverized products such as wood flour, husks such as rice husks and grains, pulverized products thereof, vegetable fibers such as jute and kenaf or pulverized products thereof, waste wood, cardboard, waste paper And pulverized products such as Two or more kinds of these plant-based fillers may be used in combination. In particular, wood flour is preferably used. A preferred mode of use of the plant filler is a granular material in which the ratio of the granular material having a powder particle size of 1000 μm or less is 80% by weight or more. Plant fillers (especially wood flour) in such a particle size range are blended more uniformly when the components are kneaded. As a result, a composite resin composition having better mechanical properties and water resistance can be obtained.

  Component (B) is a polyolefin, and specific examples thereof include high density polyethylene, medium density polyethylene, low density polyethylene, polypropylene, polybutene, poly-4-methylpentene-1, a copolymer of ethylene and α-olefin, propylene. And a copolymer of α-olefin and a mixture of two or more of these. Among these, polypropylene is preferable from the viewpoints of cost and physical properties. The MFR and density of the polyolefin are not particularly limited and can be selected according to the application and molding method. The polyolefin may be a polyolefin recovered from home appliances, containers, automobiles, and the like.

  Component (C) is a modified polyolefin having a specific MFR and a graft addition rate of a monomer having an acid group or an acid anhydride group in a specific range, and acts as an affinity material. In the present invention, the reason why the MFR and the graft addition rate (acid amount) are defined for the modified polyolefin is as follows.

  Regarding the action mechanism of the affinity material for the composite resin composition obtained by blending the component (C) polyolefin with the plant filler, it is considered as follows. In other words, the acid group or acid anhydride group of the grafted monomer forms a chemical affinity with the plant filler functional group, and the polyolefin portion as the graft trunk is entangled with the polyolefin as the matrix, so that the polyolefin and the plant High interaction is provided between the system fillers, and the plant fillers are well dispersed in the polyolefin matrix. Therefore, the amount of the grafted monomer affects the action with the filler functional group, and the molecular weight of the modified polyolefin shown by MFR greatly affects the entanglement with the molecular chain of the polyolefin, which is a matrix, and these are obtained. This affects the mechanical properties and water resistance of the composite resin composition.

  In short, if the MFR is out of the specified range no matter how high the acid amount, the entanglement with the polyolefin matrix becomes insufficient, and if the graft addition rate is low even if the MFR is in the specified range, The effect on the group is lowered, and as a result, the affinity performance is lowered.

  That is, as an affinity material, the mechanical properties and water resistance of a composite resin composition obtained by blending a plant filler into a polyolefin are improved by using a modified polyolefin having an MFR and a graft addition rate within the specific range in the present invention. I can do it. In addition, by molding such a composite resin composition, a molded body having excellent mechanical strength and water resistance and having an appearance of a plant filler system can be obtained.

  The definition of graft addition rate (acid amount) in the present invention means the amount of grafted acid groups or acid anhydride groups excluding unreacted monomers. The reason is as follows. That is, a modified polyolefin grafted with a monomer having an acid group or an acid anhydride group is usually formed from a mixture of graft polyolefin, unreacted monomer and unreacted polyolefin in which the monomer is bonded to the polyolefin main chain by a graft reaction, The ratio (molar ratio) between the bound monomer and the unreacted monomer is influenced by the reaction method and conditions, and varies in a wide range from 3: 7 to 9: 1. Since this unreacted monomer is not bonded to the polyolefin, the balance between lipophilicity and hydrophilicity is not achieved, and the action of the blend of the plant filler such as wood flour with the polyolefin is low. . Therefore, in the present invention, the graft addition rate (acid amount) after removing the unreacted monomer by the method shown in the examples is used.

  Examples of the monomer having an acid group or an acid anhydride group include acrylic acid, methacrylic acid, maleic acid, fumaric acid, maleic anhydride, and itaconic anhydride. These may be used in a mixture of two or more. Of these, maleic anhydride is preferred. By using maleic anhydride, a composite resin composition having more excellent physical properties can be obtained.

  Examples of the modified polyolefin include maleic anhydride-modified polyethylene, maleic anhydride-modified polypropylene, acrylic acid-modified polyethylene, and acrylic acid-modified polypropylene. These may be used in a mixture of two or more. Among these, maleic anhydride-modified polypropylene is preferable. By using maleic anhydride-modified polypropylene, it is possible to obtain a composite resin composition which is inexpensive and has more excellent physical properties.

  The modified polyolefin in the present invention can be obtained by reacting a monomer having an acid group or an acid anhydride group with an organic peroxide. Examples of the reaction method include a heat-mixing method using a vessel-type large reactor having a stirrer and using an organic solvent as necessary, a melt-kneading method using an extruder, etc. The melt kneading method is preferable from the viewpoint that can be obtained.

  The MFR of the modified polyolefin in the present invention should be in the range of 4 to 700 g / 10 min, preferably in the range of 5 to 500 g / 10 min, as a value measured under conditions of 180 ° C. and 21.2 N load. . When the MFR is less than 4 g / 10 min, the interaction between the modified polyolefin and the plant filler decreases, and when it exceeds 700 g / 10 min, the entanglement between the modified polyolefin and the polyolefin becomes insufficient, resulting in the resulting composite The water resistance and mechanical strength of the resin composition are lowered.

  In the modified polyolefin in the present invention, the graft addition rate of the monomer having an acid group or an acid anhydride group should be in the range of 0.10 to 5.0% by weight, preferably 0.15 to 3.0% by weight. Range. When the graft addition rate of the monomer is less than 0.10%, the interaction between the modified polyolefin and the plant filler is lowered, and the water resistance and mechanical strength of the resulting composite resin composition are lowered. When the ratio exceeds 5.0%, the balance between the addition monomer and the trunk polyolefin is lost, the mechanical strength of the resulting composite resin composition is lowered, the production difficulty of the modified polyolefin is increased, and the production cost is greatly increased. To increase. In addition, the modified polyolefin in this invention should just have the graft addition rate after removing an unreacted monomer satisfying the said range, and may contain the unreacted monomer.

  Component (D) is an inorganic filler, and specific examples thereof include talc, clay, mica, calcium carbonate, marble powder and various metal powders. These may be used alone or in combination of two or more. Furthermore, glass fiber and carbon fiber can also be used as needed.

  In the composite resin composition of the present invention, the ratio of components (A) :( B) is 40 to 90% by weight: 10 to 60% by weight, preferably 50 to 90% by weight: 10 to 50% by weight (however, both components) Is 100% by weight). When the ratio of the component (A) is less than 40% by weight, the mechanical strength is lowered, the plant fiber texture is lowered from the appearance of the obtained molded product, and the product value is lowered. It is far from the original purpose of effective use of things. On the other hand, when the ratio of the component (A) exceeds 90%, the dispersion into the component (B) is deteriorated, and the water resistance and mechanical strength of the resulting composite resin composition are lowered.

  In the composite resin composition of the present invention, the ratio of the component (C) when the total of the components (A) and (B) is 100 parts by weight is 1 to 15 parts by weight, preferably 1 to 10 parts by weight. . When the ratio of the component (C) is less than 1 part by weight, the dispersion of the component (A) with respect to the component (B) becomes poor, and the water resistance and mechanical strength of the resulting composite resin composition are lowered. When the ratio of the component (C) exceeds 15 parts by weight, the ratio of the component (C) to the component (B) increases, resulting in a decrease in thermal stability and mechanical strength and an increase in production cost.

  In the present invention, component (D), which is an optional component, is used for improving water resistance, dimensional stability, and thermal stability. The ratio of component (D) is determined according to the use and required performance of the molded article, but is usually 30% by weight or less with respect to the total amount of components (A), (B), and (D). When the ratio of the component (D) exceeds 30% by weight, the plant fiber texture is lowered from the appearance of the obtained molded product and the product value is lowered, and the dispersion becomes worse and the water resistance and mechanical strength are lowered. Sometimes. The lower limit is usually 1% by weight.

  In addition to the above-mentioned components, the composite resin composition of the present invention contains various additives such as a heat stabilizer, a weather stabilizer, an antistatic agent, a lubricant, a nuclear material, a flame retardant, a pigment, and a dye as necessary. Appropriate amount can be added.

  The composite resin composition of the present invention can be produced by, for example, a kneader, a kneader ruder, a roll, a Banbury mixer or the like using a mixer or a single-screw or twin-screw extruder, and a method of melt-kneading the above components. I can do it. By melt-kneading, the components are uniformly mixed, and a more stable mechanical resin composite resin composition can be obtained.

  Next, the molded product of the present invention will be described. The molded product of the present invention is characterized by comprising the above-mentioned composite resin composition. And the molded object of this invention is manufactured by well-known shaping | molding methods, such as sheet | seat extrusion molding, profile extrusion molding, and injection molding, selected according to a use. In molding, in addition to using the above-mentioned composite resin composition pellets, a method of using the above-described components and molding together with the composition may be employed. In particular, extrusion molding has an advantage that a molded article having good physical properties and a woody appearance can be obtained.

  The application of the composite resin composition (molded article) of the present invention is not particularly limited, and can be used in many fields where thermoplastic resins have been used conventionally. It can be preferably used in various fields such as insulating materials, especially for construction. Specifically, baseboards, door materials, floor materials, ceiling materials, the wall materials, outer wall materials, garden deck materials, bench materials, vanity materials, counter materials, window frame materials, surrounding wood, handrail materials, Handle materials, structural materials, civil engineering corner materials, formwork materials, shielding plates, sound insulation plates, furniture box ceilings, doors, shelves, curtains, decks, backboards, seats, kitchen materials, waterproofing materials, mold prevention materials Can be used for ant-proof material, shutter panel, waist panel, side panel, bus unit floor van, TV, various cabinets, scaffolding materials, surface decorative panel, piano and organ parent plate, large roof, roll roof, top and bottom scrolls.

  EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded. The physical property measuring methods and materials used in the following examples are as follows.

<Method for measuring physical properties>
(1) Particle size of wood flour:
8 types of JIS test sieves (conforming to JIS Z 8801-1) are set on Yazawa Chemical's low-tap vibratory sieve and processed for 15 minutes under conditions of 150 vibrations / minute and 75 hammers / minute. The weight ratio of each particle size was obtained by sufficient fractionation, and are summarized in Table 1.

(2) MFR:
A sample was set in an MFR testing machine manufactured by Takara Industries Co., Ltd., a load of 21.2 N was applied at a predetermined temperature, and measurement was performed according to the method of JIS K 6921-2.

(3) Removal of unreacted monomer from the modified polypropylene and measurement of the amount of grafted monomer after removal:
A 1 L separable flask equipped with a stirrer and a reflux condenser was charged with 2 g of a sample (modified polypropylene) and 200 cc of xylene, heated with a mantle heater and stirred for 30 minutes under reflux to completely dissolve the sample. Thereafter, cooling was started, and when the xylene temperature became 80 ° C. or lower, 800 cc of acetone was dropped. The deposited precipitate was separated with a filter, and then thoroughly rinsed with 2000 cc of acetone. Then, using the vacuum dryer kept at 60 degreeC, acetone was volatilized from precipitation and the modified polypropylene which removed the unreacted monomer was obtained. The precipitate after drying was pressed and the maleic anhydride graft addition rate was quantified by IR method. The modified polypropylene A had a maleic anhydride graft addition rate of 0.52% by weight before removal of unreacted monomers and a maleic anhydride graft addition rate of 0.35% by weight after removal. Similarly, with respect to the modified polypropylenes B to H, the maleic anhydride graft addition rate after removal of the unreacted monomer was determined and arranged in Table 3.

(4) Bending strength of sheet:
The measurement was performed according to JIS K7171.

(5) Sheet tensile strength:
The measurement was performed according to JIS K7113.

(6) Sheet water absorption:
Using a sample of 90 mm × 90 mm, measuring the weight (W1) after vacuum drying (10 mmHg) at 50 ° C. × 24 hours, then measuring the weight (W2) after being immersed in pure water at 23 ° C. for 24 hours, The weight percentage of the weight increase was determined by the following formula.

<Material>
(1) Plant filler:
A wood flour having a ratio of 90% by weight of particles having a particle size of 1000 μm or less was used. The particle size distribution is as shown in Table 1.

(2) Inorganic filler:
Talc with an average particle size of 0.5 μm was used.

(3) Polyolefin:
Polypropylene (PP) described in Table 2 below was used.

(4) Modified polyolefin (affinity material):
Maleic anhydride-modified PP shown in Table 3 was used. Among them, the modified PP (G) and (H) used in the comparative examples are commercially available low molecular weight maleic anhydride-modified PP, and their number average average molecular weights are 15,000 and 4,000, respectively. .

Examples 1-16 and Comparative Examples 1-10:
Preliminarily mixed predetermined parts by weight of each component described in Tables 4 to 7, using a lab plast mill manufactured by Toyo Seiki Co., Ltd., melt-kneaded for 2 minutes under the conditions of a preset temperature of 200 ° C. and a rotational speed of 80 rpm, and a composite resin composition I got a thing. A sheet with a thickness of 2 mm was prepared from this composite resin composition by a press sheet molding method, and subjected to physical property measurement. All the obtained sheets had a woody appearance.

Claims (9)

  Component (A): Plant-based filler, Component (B): Polyolefin, Component (C): MFR measured under conditions of 180 ° C. and 21.2 N load is in the range of 4 to 700 g / 10 min, and an acid group or It comprises a modified polyolefin in which the graft addition ratio of the monomer having an acid anhydride group is in the range of 0.10 to 5.0% by weight, and the ratio of components (A) :( B) is 40 to 90% by weight: 10 -60 wt% (however, the total of both components is 100 wt%), and the ratio of component (C) is 1-15 parts by weight when the total of components (A) and (B) is 100 parts by weight And a composite resin composition.   The component (D): comprising an inorganic filler, and the ratio thereof is 30% by weight or less based on the total amount of the components (A), (B), and (D). Composite resin composition.   The composite resin composition of Claim 1 or 2 obtained by melt-kneading each component.   The composite resin composition according to any one of claims 1 to 3, wherein the component (A) is wood flour.   The composite resin composition according to any one of claims 1 to 4, wherein the component (A) is a granular material, and a ratio of the granular material having a particle size of 1000 µm or less is 80 wt% or more.   The composite resin composition according to any one of claims 1 to 5, wherein the component (B) is polypropylene.   The composite resin composition according to claim 1, wherein the monomer having an acid anhydride group is maleic anhydride.   The composite resin composition according to any one of claims 1 to 7, wherein the component (C) is maleic anhydride-modified polypropylene.   A molded article comprising the composite resin composition according to any one of claims 1 to 8.