JPS6140707B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a resin composition that has excellent rigidity, bending strength, machinability, etc. and can provide a foamed molded product suitable for synthetic wood, particularly for pencil shafts, a foamed molded product thereof, and a method for producing the same. Traditionally, natural wood is generally used for pencil barrels, but in order to improve rigidity and cutting properties, special wood, such as incense tree with specific annual rings, is selected, and then treated with oil. It uses something that has been subjected to complicated processing such as. However, such natural wood requires a complicated process for inserting the core, and has drawbacks in terms of productivity, cost, etc. On the other hand, synthetic pencil shafts based on plastic have been proposed to replace natural wood. For example, Japanese Patent Publication No. 4519124 proposes a pencil shaft made of a composition of polypropylene, aliphatic amide, talc, and the like. Also Tokko Akira
No. 47-26014 proposes a pencil shaft made of a foam such as a styrene resin, and Japanese Patent Publication No. 49-2134 proposes a pencil shaft made of a styrene resin foam containing short glass fibers. Furthermore, Japanese Patent Application Laid-Open No. 16214/1983 proposes a composition for pencil barrels in which a filler and glass fiber are added to a mixed composition of polystyrene and polyethylene. On the other hand, Utility Model Publication No. 36-3412 and Utility Model Publication No. 51-348 propose the use of foamed synthetic resin as the shaft of a pencil. The inventors of the present invention have carefully tried and evaluated the examples disclosed in the above-mentioned several publications, and compared them with pencils made of natural wood.The inventors have found that although each of these synthetic pencil stems has various advantages, there are some commonalities. It was discovered that polyolefin-based materials have the disadvantage of low rigidity and bending strength and cannot be handled like wood, while styrene resin-based materials have poor machinability. In addition, if simply foamed synthetic resin is used for the pencil shaft as in Utility Model Publication No. 36-3412 and Utility Model Publication No. 51-348, the physical and chemical properties of the shaft are Because it is greatly influenced by the original properties of the synthetic resin used, more than its form and structure,
However, we reached the conclusion that unless we developed a synthetic resin with properties suitable for pencil shafts, it would be impossible to create truly suitable pencil shafts. The present inventors proceeded with research based on this viewpoint,
The above-mentioned drawbacks of the synthetic resin shaft have been improved, and rigidity has also been improved.
Regarding the development of synthetic wood that has excellent properties such as bending strength and machinability, especially as a pencil shaft, we continued to study plastic materials and combinations of various plastic materials with various inorganic fillers, and finally published a book. This invention has been achieved. That is, the present invention provides a synthetic main material suitable for use in pencil barrels, (a) 40 to 80% by weight of polyolefin, (b) 5 to 50% by weight of plate-shaped or needle-shaped inorganic filler, and (c) Glass fiber 5. ~30% by weight, and (d) 0.1 to 10% by weight of an organic compound having at least one ethylenically unsaturated bond and at least one hydroxyl group in the molecule, especially a resin composition that is a heat-kneaded reaction product. The present invention provides a foamed molded product. The main features of the foam molded product of the present invention are listed below. 1 Excellent mechanical properties such as rigidity and bending strength. 2. Excellent creep properties, with little creep deformation due to bending, tension, etc. 3. Excellent heat resistance and can be used in a wide temperature range from low to high temperatures. 4 Excellent machinability and easy machining. 5. Excellent impact resistance and can be easily nailed. 6. It is lightweight and easy to use. 7 In view of the above features, it is particularly suitable as a pencil shaft, but it can also be used in a wide range of other applications such as various structural members and building materials. Although the mechanism of action that exerts these distinctive properties is not necessarily clear, it is difficult to form fine, uniform cells during foaming when the organic compound is not used, that is, when a mixture of polyolefin, inorganic filler, and glass fiber is used. Considering that the mechanical strength of the foam molded product is low, the organic compound constitutes a bond with the inorganic filler, the glass fiber, and the polyolefin, and this strong bond supports the cells of the molded product. It has sufficient strength to
It is estimated that this helps in making the foam cells uniform and fine. Below, regarding the embodiments of the present invention,
explain. The polyolefin in the present invention refers to one whose main component is a polymer or copolymer of monoolefin such as ethylene, propylene, butene.
For example, high density polyethylene, medium and low density polyethylene, crystalline polypropylene, crystalline ethylene-propylene block copolymer, polybutene,
Refers to poly-3-methylbutene-1, poly-4-methylpentene-1, etc., and mixtures thereof. In particular, when the main purpose of the present invention is a pencil shaft or the like, high-density polyethylene, a mixture of high-density polyethylene and medium or low-density polyethylene, or a mixture of these three, high-density polyethylene and crystalline polypropylene are used. or crystalline ethylene
A mixture with a propylene block copolymer or a mixture of the three of them, and among these mixtures, those containing high-density polyethylene as the main component are preferred in terms of balancing various physical properties such as rigidity and machinability. In addition, even when using only high-density polyethylene, it is also possible to mix two or more types of high-density polyethylene with different molecular weights, molecular weight distributions, densities, etc. to improve moldability and physical properties of molded products. In particular, it is preferable to select ultra-high molecular weight polyethylene having a high molecular weight as one of the components in order to stabilize the cell structure and further improve the physical properties of the molded product. The inorganic filler used in the present invention is an inorganic powder having a plate-like or needle-like particle shape, and examples thereof include the following. These include talc, kaolin clay, mica, montmorillonite, basic magnesium carbonate, and wollastonite. These inorganic fillers can be used alone or in a mixture of two or more. Among the fillers,
Particularly preferred in the present invention are talc and mica. The average particle size of the inorganic filler is 0.1~50μ
It is preferable that the In addition, a small amount of calcium oxide, magnesium oxide, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, calcium carbonate, magnesium carbonate, sodium aluminosilicate, potassium aluminosilicate, lithium aluminosilicate, calcium sulfate, sulfuric acid may be added to the inorganic filler. It is desirable to mix a fine powdery inorganic filler such as barium in order to stabilize the cell structure of the molded article of the present invention. The amount of the inorganic filler used in the present invention varies depending on the physical properties expected of the final foamed molded product, but
The amount is in the range of 5 to 50% by weight, preferably 10 to 45% by weight in the foam molded product. The concentration of the inorganic filler is 5% by weight
In the following cases, there is no substantial difference in physical properties from that of a foam molded product made of a single blend of glass fibers. Also,
If it exceeds 50% by weight, the surface of the foam molded product tends to become rough, making foam molding difficult, which is not preferable. The glass fiber used in the present invention is generally used for reinforcing plastics, and preferably has a fiber diameter of 1 to 20 microns. In addition, glass fiber
Although it is possible to use materials that have undergone various silane treatments or those that have not, those that have been subjected to such surface treatments are more preferable. The amount of glass fiber used in the present invention varies depending on the physical properties expected of the final foamed molded product, but
The amount is in the range of 5 to 30% by weight, preferably 10 to 25% by weight in the foam molded product. When the concentration of the glass fiber is 5% by weight or less, no synergistic effect between the glass fiber and the inorganic filler is exhibited. On the other hand, if the concentration of the glass fiber is 30% by weight or more, it is not preferable because the cell structure is not stable and the machinability of the final foamed molded product is deteriorated. The organic compound that can be used in the present invention and has at least one ethylenically unsaturated bond and at least one hydroxyl group in its molecule is CH ₂ =CH-COO(CH ₂ CH ₂ O) _k H, k ≧1 _CH2 =C( _CH3 )H-COO( _CH2CH2O ) _1H , ₁
≧1 CH ₂ = CH−COO (CH ₂ C (CH ₃ ) HO) _n H, m ≧
1 _CH2 =C( _CH3 )H−COO( _CH2C ( _CH3 )HO) _o
Compounds represented by H, n≧1, such as monoesters of acrylic acid and methacrylic acid of ethylene glycol, propylene glycol, or their polymers, and compounds other than these include 2-hydroxypropyl monoacrylate, 2-hydroxy Propyl monomethacrylate, 3-chloro-2-
Hydroxypropyl monoacrylate, etc. In the present invention, the organic compound used has a molecular weight of 10,000 or less, preferably 5,000 or less. The amount of the organic compound used in the present invention is from 0.1 to 10% by weight, preferably from 0.3 to 8% by weight of the composition. When the amount of the organic compound used is less than this range, the physical properties of the final foamed molded product are the same as those when the organic compound is not used. On the other hand, if the amount exceeds this range, troubles such as generation of secondary aggregates and oozing of the organic compound tend to occur, making it impossible to obtain a desirable molded product. In the present invention, (a) the polyolefin, (b) the inorganic filler, (c) the glass fiber, and (d) the organic compound are heated and kneaded. In this case, 4 above
or (a), (b) and (d), (a), (b) and (c), (a) and (b),
There is a method of heating and kneading the two materials (a) and (c) in advance, and then adding the remaining portion and kneading with heat. As the heating kneading device, commonly used kneading machines such as various extruders, Banbury mixers, kneaders, mixing rolls, etc. can be used. Further, it is recommended to carry out premixing continuously or intermittently before heating and kneading. especially,
(b) and (d) or (b), (c), and (d) are premixed in advance, and (d) is reacted or adsorbed on the surfaces of (b) and (c). It is preferable to heat and knead after bonding with a method such as the like. As the premixing device, various mixing devices are preferred, generally high efficiency mixers such as Henschel mixers, Muellers, ribbon blenders and the like. Furthermore (b),
In order to increase the contact efficiency between (c) and (d), (d) is atomized,
Alternatively, it is desirable to add it in gaseous form. If the organic compound used at this time is a liquid with relatively low viscosity, it is preferable to use it as is, but if it is a liquid or solid with relatively high viscosity, use a small amount of non-polar solvent as necessary. Good too. The temperature during premixing must be appropriately selected depending on the type, combination, properties, etc. of (b), (c), and (d) used, and is between room temperature or higher and lower than the decomposition temperature of (d). Generally, a temperature range of 50 to 200°C is preferred. Further, the mixing time is appropriately selected depending on various conditions, but a time range of 1 to 30 minutes is generally preferred. Furthermore, in order to avoid polymerization of (d) during mixing, it is preferable to appropriately select the reaction atmosphere or add a polymerization inhibitor to (d). Polymerization inhibitors include hydroquinone, methoxyhydroquinone, P-benzoquinone, naphthoquinone, t
- General polymerization inhibitors such as butylcatechol can be used, and the recommended amount is 0 to 1% by weight, particularly 0.02 to 0.5% by weight based on (d). Furthermore, the mixing must be carried out in the substantial absence of liquid water, and is preferably carried out under conditions such that water generated during mixing is removed from the system (dehydration conditions). Therefore, it is desirable that (b), (c) and (d) be dehydrated and dried before use. It is also possible to adopt a method in which the above-mentioned heating kneading and the later-described foam molding are performed simultaneously. In this case, the above (a),
The four components (b), (c), and (d) can be premixed with various components such as a blowing agent to be described later, and the premix can be heated and kneaded in a molding machine and simultaneously subjected to foam molding. The temperature of heating and kneading is in the range above the melting and softening temperature of the base polymer and below the thermal decomposition temperature, but in order to increase the effect of improving the physical properties of the molded product, the temperature should be 180℃ or above.
Preferably, the temperature is in the range of 300°C or less. In addition, in order to obtain particularly excellent high-performance materials,
It is preferable to use a radical generator during heating and kneading. By using a radical generator, the cell structure of the resulting foamed molded product is stabilized, and the balance between mechanical strength and machinability is further improved. In this case, usable radical generators include tetravalent tin compounds such as dibutyltin oxide,
2,5-dimethyl-2,5-di(t-butylperoxy)hexane, 2,5-dimethyl-2,5-
Di(t-butylperoxy)hexyne-3, dicumyl peroxide, t-butylperoxymaleic acid, lauroyl peroxide, benzoyl peroxide, t-butyl perbenzoate,
Commonly used radical generators such as organic peroxides such as t-butyl hydroperoxide and isopropyl percarbonate, azo compounds such as azobisisobutyronitrile, and inorganic peroxides such as ammonium persulfate. You may use one or a combination of two or more of them. The amount of the radical generator used is usually in the range of 0.001 to 0.5 parts by weight, preferably 0.01 to 0.5 parts by weight, based on 100 parts by weight of the composition. In the present invention, the composition is then molded into a desired foam molded article. Various commonly used foam molding methods can be used to obtain the foam molded product. For example, pentane,
Foaming methods using volatile blowing agents such as low-boiling hydrocarbons such as butane and propane, solvents such as petroleum ether and vinyl chloride monomers, foaming methods using nitrogen gas, and inorganic chemicals such as sodium bicarbonate and ammonium carbonate. There is a method of foaming using an organic chemical foaming agent such as a hydrazine-based, nitroso-based, or azo-based foaming agent. Among these various methods, the preferred method in the present invention is a method using an organic or inorganic chemical blowing agent. In such foaming methods, various foaming aids are used, such as urea foaming aids, organic acid foaming aids such as stearic acid, lauric acid, and salicylic acid, and metal salt foaming aids such as calcium stearate and zinc stearate. This is a preferred method for obtaining a foam molded article having a high level of physical properties in the present invention. In addition, in the present invention, a more preferable method for obtaining a foamed molded product includes dibutyl phthalate, dibutyl phthalate,
There are methods using various plasticizers such as di-2-ethylhexyl phthalate and diisodecyl phthalate, and various wetting agents such as ethylene monomer, low-viscosity polybutene, and chlorinated paraffin. Among these wetting agents, low-viscosity polybutene is particularly recommended. By using such a wetting agent, the cells in the resulting foamed molded product become finer, become closed cells, and are uniformly dispersed, making it possible to obtain a foamed molded product with higher physical properties. In addition, in the foam molded product of the present invention, the cell structure can be selected depending on the application, such as a uniform structure for both the inner layer and the outer layer, or a structure consisting of an outer layer with a smaller expansion ratio than the inner layer. When used for a shaft, it is desirable that the outer layer has a smaller expansion ratio than the inner layer. Furthermore, the surface of the molded product can be painted or coated with various paints or resins for various purposes. In the present invention, due to the use of the organic compound and the fine cell structure, these paintability and coating properties are extremely good. The degree of foaming of the foamed molded product in the present invention is such that the expansion ratio (specific gravity of unfoamed composition/apparent specific gravity of foamed molded product) is in the range of 1.1 to 4.0, more preferably 1.2.
~3.0 range. If the foaming ratio is lower than this, machinability is poor, and if it is higher than this, the level of physical properties is low, and in particular, brittleness increases, which is undesirable. As a method for manufacturing a pencil shaft, which is one of the major objects of the present invention, various commonly used methods can be applied. For example, a method of co-extruding a foam molded body with a core, a method of inserting a core into two foam molded bodies and gluing the molded bodies together, a method of molding a foam molded body with a cavity and attaching a core to it. There are methods such as inserting and gluing. The surface that adheres to the core, the surface that becomes the so-called cavity, may be rough or smooth, but a smooth surface is preferable for the following reasons. In other words, since polyolefin is used as the raw material in the present invention, its shrinkage rate is higher than that of styrene-based resins, etc.; Since the foamed molded part contracts, it improves adhesion to the core and increases resistance to core removal. In this case, if the surface corresponding to the cavity is rough, the contact area between the core and the surrounding foam molded portion will be reduced, and the adhesion between the core and the surrounding foam molded portion will be reduced. In addition to the above composition, the foam molded product of the present invention includes various stabilizers, lubricants, crosslinking agents, pigments, flame retardants,
It may also contain additives such as antistatic agents. In particular, when used as a pencil shaft, it is preferable to add an antistatic agent to improve the cutting properties, prevent dust from adhering, and increase practicality and commercial value. The present invention will be explained in more detail below using examples, but the scope of the present invention is not limited only to the scope of the examples. In addition, parts and % in Examples and Reference Examples are parts by weight and % by weight, respectively. Example 1-1 Talc powder 50 with an average particle size of 9μ and a moisture content of 0.12%
Glass fiber (CS-3PE-401 manufactured by Nitto Boseki Co., Ltd.)
Put 100 parts of the mixture with 50 parts into a Henschel mixer, heat it to 100°C and while stirring, add 4 parts of ethylene glycol monoacrylate containing 300 ppm of hydroquinone, mix and stir at normal pressure for 30 minutes, A mixed filler of talc powder, glass fiber and ethylene glycol monoacrylate was produced. 45 parts of the above mixed filler, melt index (hereinafter referred to as MI) (load 2.16 kg, temperature 190°C) 4.2, 55 parts of high-density polyethylene powder with a specific gravity of 0.965, and 2,5-dimethyl-
2,5 di(t-butylperoxy)hexane 0.03
pre-mix the parts in a ribbon blender and blend the mixture into
The pellets were extruded using a 65 mm extruder at an extrusion temperature of 250°C to obtain pellets with an average particle size of about 2 mm. Next, 0.1 part of polybutene was mixed with 100 parts of the pellets, followed by 0.5 part of calcium stearate, 0.5 part of azodicarbonamide, and 0.3 part of an antistatic agent (Electro Stripper EA, manufactured by Kao Soap Co., Ltd.). The mixture thus obtained is extruded and foamed using a 65 mm extruder at a set temperature of 200°C through a hexagonal die with a cross section of 7 mm on each side. was molded. On the other hand, when performing the foam molding, the lead is extruded using a 40 mm extruder, and this lead can be co-extruded into the center of the pencil shaft, resulting in a pencil in which the lead is inserted at the same time as the foam molding. I did it like that. The synthetic pencil thus produced had a lead inserted in the center of the cross section, and the shaft consisted of an inner layer made of extremely fine closed cells and an outer layer with a low expansion ratio. Regarding this pencil, the apparent density of the shaft portion, the expansion ratio, the maximum bending stress of the pencil, and the bending elastic modulus were measured to evaluate the cutting property. The bending properties were measured in an atmosphere of 20°C, with a distance between fulcrums of 100 mm, and a loading rate of 10 mm/min. The evaluation of machinability was based on the cutting resistance using an electric cutter, the sharpness of the tip when cutting manually with a knife, and the visual judgment of the shape of the cut piece. In this case, the acute angle of the tip is 5 points for natural wood products,
A score of 1 is given if the wood cannot be cut to an almost acute angle, and the higher the score, the closer it is to natural wood. Further, the shape of the cut pieces was rated A for a regular flake shape, B for an irregular flake shape, and C for a grain shape. These evaluation results are shown in Table 1. Example 1-2 Using the raw materials used in Example 1-1, the composition was as shown in Table 1, and a synthetic pencil was manufactured using the same manufacturing, molding method and conditions as in Example 1-1. was manufactured. The synthetic pencil thus produced was evaluated in the same manner as in Example 1-1. The evaluation results are shown in Table 1. Reference Example 1-1 Three ingredients, ethylene glycol monoacrylate, radical generator, and antistatic agent, were removed from the raw materials of Example 1-1 and blended into the composition shown in Table 1,
A synthetic pencil was manufactured using the same conditions as in Example 1-1 for other composition manufacturing conditions and foam molding conditions. This synthetic pencil was evaluated in the same manner as in Example 1-1. The evaluation results are shown in Table 1. Reference Example 1-2 Three ingredients, ethylene glycol monoacrylate, radical generator, and antistatic agent, were removed from the raw materials of Example 1-2 and blended into the composition shown in Table 1,
A synthetic pencil was manufactured using the same conditions as in Example 1-1 for other composition manufacturing conditions and foam molding conditions. This synthetic brush was evaluated in the same manner as in Example 1-1. The evaluation results are shown in Table 1. Reference Example 1-3 Regarding commercially available natural wood pencils, Example 1-1
The maximum bending stress, bending modulus, and machinability were evaluated in the same manner as above. The evaluation results are shown in Table 1. Reference example 1-4 Example 1-1 regarding commercially available synthetic resin pencils
The maximum bending stress, bending elastic modulus, and machinability were evaluated in the same manner as above. The evaluation results are shown in Table 1. Reference Example 1-5 In Example 1-1, an unfoamed synthetic pencil was produced by removing polybutene, foaming agent, calcium stearate, and antistatic agent from the raw materials,
They were evaluated in the same way. The evaluation results are shown in Table 1. Reference Example 1-6 In Reference Example 1-1, an unfoamed synthetic pencil was produced in which polybutene, blowing agent, and stearic acid were removed from the raw materials, and evaluated in the same manner. The evaluation results are shown in Table 1.

[Table] Example 2-1 45 parts of talc powder with an average particle size of 6μ, a BET specific surface area of 10m ² /g, and a moisture content of 0.15% and an average particle size of 1.8
μ, 5 parts of calcium carbonate powder with a BET specific surface area of 5.5 m ² /g and the glass fiber used in Example 1-1
Put 100 parts of the mixture with 50 parts into a Henschel mixer, heat it to 80°C and while stirring, add 3 parts of polyethylene glycol monoacrylate containing 300 ppm of hydroquinone, mix and stir at normal pressure for 30 minutes, A mixed filler of talc, calcium carbonate, glass fiber and polyethylene glycol monoacrylate was produced. 2,5-dimethyl-2 was added to a mixture of 40 parts of the mixed filler, 40 parts of high-density polyethylene with an MI of 6.5 and a specific gravity of 0.96, and 20 parts of polypropylene with an MI of 1.5 and a boiling n-heptane insoluble content of 94%. After adding 0.02 parts of 5-di(t-butylperoxy)hexane and mixing well with a Henschel mixer, this mixture was extruded with a 65 mm extruder while heating and kneading at a temperature of 250°C, pelletized, and the average A pellet-like composition with a particle size of about 2 mm was produced. Mix 1.0 part of polybutene with 100 parts of the pellets,
Next, 0.5 part of calcium stearate, 0.4 part of azodicarbonamide, and 0.8 part of the antistatic agent used in Example 1-1 were mixed. The mixture thus obtained was used in Example 1-1.
A synthetic pencil was made using the foam molding equipment used in Example 1-1, with the cylinder temperature set at 200°C, and in the same manner as in Example 1-1. The synthetic pencil thus produced had a lead inserted in the center of the cross section, and the shaft consisted of an inner layer made of extremely fine closed cells and an outer layer with a low expansion ratio. This pencil had extremely good adhesion between the lead and the shaft, and the lead did not fall out. The pencil thus produced was evaluated for apparent density, expansion ratio, maximum bending stress, bending elastic modulus, and machinability in the same manner as in Example 1-1. These evaluation results are shown in Table 2. Example 2-2 Each raw material used in Example 2-1 was blended with the composition listed in Table 2, and a method for producing a filling composition was performed.
Conditions, synthetic pencil molding method, and conditions are as in Example 2-1.
A synthetic pencil was produced in the same manner. The pencil thus produced was evaluated for apparent density, expansion ratio, maximum bending stress, bending elastic modulus, and machinability in the same manner as in Example 1-1. These evaluation results are shown in Table 2. Example 2-3 A synthetic pencil was produced in the same manner as in Example 2-1 except that among the raw materials in Example 2-1, polyethylene glycol monoacrylate was replaced with propylene glycol monomethacrylate. The pencil thus produced was evaluated in the same manner as in Example 2-1. These evaluation results are shown in Table 2. Reference Example 2-1 A synthetic pencil was prepared in the same manner as in Example 2-1, except that three components, polyethylene glycol monoacrylate, radical generator, and antistatic agent, were removed from the raw materials used in Example 2-1. was produced. The pencil thus produced was evaluated in the same manner as in Example 2-1. These evaluation results are shown in Table 2. Reference Example 2-2 A synthetic pencil was prepared in the same manner as in Example 2-2, except that three components, polyethylene glycol monoacrylate, radical generator, and antistatic agent, were removed from the raw materials used in Example 2-2. was produced. The pencil thus produced was evaluated in the same manner as in Example 2-1. These evaluation results are shown in Table 2.

【table】

[Table] Example 3 In Example 1-1, talc powder was
A synthetic pencil was produced and evaluated in the same manner as in Example 1-1, except that 10μ mica powder was used instead. These evaluation results are shown in Table 3. Reference Example 3 In Reference Example 1-1, talc powder was used in Example 3.
Reference Example 1- except that the mica powder used in was replaced.
A synthetic pencil was produced and evaluated in the same manner as in Example 1. These evaluation results are shown in Table 3.

【table】

[Table] Example 4 In Example 1-1, acicular wollastonite (92% under 20μ) was used as the inorganic filler, ethylene glycol monomethacrylate was used as the organic compound, and N,N'-dinitroso was used as the blowing agent. Example 1-1 except that pentamethylenetetramine was used
A synthetic pencil was produced and evaluated in the same manner as above. The evaluation results are shown in Table 4. Reference Example 4 A synthetic pencil was prepared and evaluated in the same manner as in Example 4, except that the organic compound, radical generator, and antistatic agent were removed from Example 4, and the raw material composition was as shown in Table 4. The evaluation results are shown in Table 4.

【table】

[Table] As mentioned above, the synthetic wood of the present invention has very good physical properties, so it is extremely suitable for a wide variety of uses, such as wood substitutes such as pencil shafts. .

Claims (1)

[Scope of Claims] 1 (a) 40 to 80% by weight of polyolefin, (b) 5 to 50% by weight of plate-shaped or needle-shaped inorganic filler, (c) 5 to 30% by weight of glass fiber, and (d) Intramolecule A resin composition which is a heat-kneaded reaction product of 0.1 to 10% by weight of an organic compound having at least one ethylenically unsaturated bond and at least one hydroxyl group. 2. The resin composition according to claim 1, which is in a foamed form. 3. The resin composition according to claim 2, which is in the form of a pencil shaft-shaped foam. 4. The resin composition according to claim 2 or 3, which has an expansion ratio (specific gravity of unfoamed composition/apparent specific gravity of foamed molded product) in the range of 1.1 to 4.0. 5. The resin composition according to claim 4, which has an expansion ratio in the range of 1.2 to 3.0. 6 (a) is 40-80% by weight, (b) is 10-45% by weight, (c) is
The resin composition according to claim 1, wherein the content of (d) is 10 to 25% by weight and 0.3 to 8% by weight. 7. The resin composition according to claim 1, wherein the polyolefin (a) is high-density polyethylene or a mixture with an olefin homopolymer or copolymer mainly composed of high-density polyethylene. 8. The resin composition according to claim 7, which contains ultra-high molecular weight polyethylene as one component. 9. The resin composition according to claim 1, wherein (b) the inorganic filler is talc or mica with an average particle size of 0.1 to 50 μm. 10 (d) The organic compound is ethylene glycol, propylene glycol, monoester of acrylic acid or methacrylic acid of polyethylene glycol or polypropylene glycol, 2-hydroxypropyl monoacrylate, 2-hydroxypropyl monomethacrylate, 3-chloro-2-hydroxy Propyl monomethacrylate, 3-chloro-2
The resin composition according to claim 1, which is at least one member selected from the group consisting of -hydroxypropyl monoacrylate and having a molecular weight of 10,000 or less. 11 In addition to (a) to (d), foaming aids, plasticizers,
Wetting agents, stabilizers, lubricants, crosslinking agents, pigments, flame retardants,
The resin composition according to claim 2 or 3, which contains one, two or more, or all of the antistatic agents selected from the group consisting of antistatic agents. 12 (a) 40-80% by weight of polyolefin, (b) 5-50% by weight of plate-like or needle-shaped inorganic filler, (c) 5-30% by weight of glass fiber, and (d) at least one ethylene in the molecule. Production of a resin composition characterized by heating and kneading 0.1 to 10% by weight of an organic compound having both a sexually unsaturated bond and at least one hydroxyl group at a temperature of 180 to 300°C, and then foaming by adding a foaming agent. Law. 13. The method for producing a resin composition according to claim 12, wherein heating kneading and foaming are performed in separate devices. 14. The method for producing a resin composition according to claim 12, wherein heating kneading and foaming are performed simultaneously in one extruder. 15. The method for producing a resin composition according to claim 12, which uses 0.001 to 0.5 parts by weight of a radical generator per 100 parts by weight of the resin composition during heating and kneading. 16 (b) and (d), or (b), (c), and (d) as 5
Premix at a temperature of ~200℃ and apply to the surfaces of (b) and (c).
After combining (d), the remaining ingredients are added and kneaded by heating in claim 12, 13 or 14.
2. Method for producing the resin composition described in Section 1. 17 Claim 16 in which the premixing is carried out in the presence of a polymerization inhibitor in an amount of 1% by weight or less based on (d)
2. Method for producing the resin composition described in Section 1.