JP3619074B2 - Method for producing molded thermoplastic resin - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a thermoplastic resin molded body.
[0002]
[Prior art]
Conventionally, a method for producing a composite thermoplastic resin molded body in which a filler such as wood powder is mixed in a thermoplastic resin such as polyethylene or polypropylene is known.
As a method for producing the composite thermoplastic resin molded body, for example, in JP-A-7-266313, a wood powder and a thermoplastic resin molding material having a water content within 15 wt% are mixed using a mixer to form a gel. A wood synthetic powder kneaded and pelletized and a method for producing a wood synthetic board by extrusion molding using the same are disclosed.
[0003]
However, the method for preparing a wood synthetic powder and the method for producing a wood synthetic board using the obtained wood synthetic powder disclosed in the above publication are pre-plasticizing steps in which wood powder is pre-kneaded into a thermoplastic resin and pelletized. And at least two steps of an extrusion process for producing a woody synthetic board using the above pellets, and further slowly cooling the extruded dough extruded to a forming die with a screw, and using the extruded dough with an extruding force In order to add a restraining force to resist, a molding die in which a fluororesin sheet is attached or coated with fluororesin on the upper, lower, left and right inner peripheral surfaces of the molding die is used. In other words, the molding die significantly reduces productivity, for example, by adding a suppressing force against the extrusion force to the extruded dough.
[0004]
[Problems to be solved by the invention]
The present invention has been made in view of the above-mentioned fact, and without causing deterioration in appearance quality due to burning of a filler such as wood powder on a thermoplastic resin molded body highly filled with a filler, and It is an object of the present invention to provide a method for producing a thermoplastic resin molded product that can be produced with high productivity in one step without unevenly dispersing the filler in the thermoplastic resin and forming a dense portion in the structure.
[0005]
[Means for Solving the Problems]
According to a first aspect of the present invention, there is provided a method for producing a thermoplastic resin molded article comprising: an extrusion molding machine provided with a shaping mold and a cooling mold directly connected thereto on the outlet side of an extruder body comprising a screw and a barrel. A method for producing a thermoplastic resin molded article that is solidified and extruded using a thermoplastic resin composition comprising a thermoplastic resin and a filler, provided between the outlet side of the extruder body and a shaping mold. The outlet inner diameter of the adapter is 80 to 100% of the barrel inner diameter of the extruder. During as well as The above adapter and shaping Mold of In the meantime, other than the reduction of the inner diameter of the adapter, no resistor is provided to block the passage of the thermoplastic resin composition, and the barrel temperature near the outlet of the extruder body is a temperature below the melting point of the thermoplastic resin. It is set and pushed out.
[0006]
According to a second aspect of the present invention, there is provided a method for producing a thermoplastic resin molded article according to the first aspect of the present invention, wherein the molding die is a method for producing a thermoplastic resin molded article according to the first aspect of the invention. Is Resin inlet cross-sectional area do it, Cross-sectional area of resin flow path in shaping mold and Of the above shaping mold The ratio of the discharge port cross-sectional area is in the range of 80 to 100%.
[0007]
The method for producing a thermoplastic resin molded article according to claim 3 is the method for producing a thermoplastic resin molded article according to claim 1 or 2, wherein the thermoplastic resin composition comprising a thermoplastic resin and a filler is used. Furthermore, an α, β unsaturated carboxylic acid monomer and a polymerization initiator are added.
[0008]
According to a fourth aspect of the present invention, there is provided a method for producing a thermoplastic resin molded body according to the first or second aspect of the invention, wherein the thermoplastic resin is a polyolefin resin and the filler is wood flour. It is characterized by being.
[0009]
The thermoplastic resin used in the present invention is not particularly limited. For example, polyethylene, polypropylene, polystyrene, vinyl chloride resin, acrylic resin, polyamide, polyacetal, polyethylene terephthalate, polybutylene terephthalate, tetrafluoroethylene. -Fluororesin such as hexafluoropropylene copolymer, tetrafluoroethylene-perfluoroalkyl vinyl ether copolymer; acrylonitrile-butadiene-styrene copolymer, ethylene-vinyl acetate copolymer, thermoplastic urethane resin, polyphenylene sulfide, polyphenylene Examples thereof include oxides and polycarbonates. Among these, thermoplastic resins having a high affinity for α, β unsaturated carboxylic acid monomers such as polypropylene, polystyrene, acrylic resins, and ethylene-vinyl acetate copolymers are preferably used.
[0010]
Although the said filler is not specifically limited, For example, plant-derived granular materials, such as wood flour, aluminum hydroxide, magnesium hydroxide, titanium oxide, magnesium oxide, molybdenum dioxide, calcium carbonate, calcium silicate , Barium sulfate, calcium aluminate hydrate, metal powder such as iron powder, ettringite, silica sand, borax, alumina, talc, kaolin, silica, mica, clay, dolomite, fly ash, talc, glass fiber, glass beads, Examples include asbestos.
These fillers may be used alone or in combination of two or more.
[0011]
The particle size or the like of the filler is not particularly limited, but if it is too small, the melt viscosity in the extruder of the blended thermoplastic resin composition becomes too high and the extrusion moldability is lowered. If it is too large, the surface properties of the resulting composite molded article will be deteriorated, so the particle size is preferably about 1 to 300 μm.
[0012]
For the purpose of increasing the miscibility with the thermoplastic resin, the above fillers may contain silane coupling agents such as vinylchlorosilane and vinyltrimethoxysilane, isopropyl triisostearoyl titanate, tetraisopropyl bis (dioctyl phosphite) as necessary. It is preferable to surface-treat the surface with a surface treatment agent such as a titanium coupling agent such as titanate.
[0013]
The blending amount of the filler is not particularly limited and is determined according to the use of the obtained composite pellet or composite molded body. However, if the amount is too small, the blending effect of the filler cannot be sufficiently exhibited. If too much, homogeneous kneading with the thermoplastic resin is difficult to be performed sufficiently, and the extrudability deteriorates.For example, when a plant-derived granular material such as wood flour is used as a filler, preferably Is 50 to 400 parts by weight, more preferably 100 to 300 parts by weight with respect to 100 parts by weight of the thermoplastic resin.
[0014]
Moreover, it is preferable that an α, β unsaturated carboxylic acid monomer and a polymerization initiator are further added to the thermoplastic resin composition containing the filler.
[0015]
The α, β unsaturated carboxylic acid monomer is not particularly limited, and examples thereof include ethyl methacrylate, butyl methacrylate, i-butyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, and tridecyl. Methacrylate, stearyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl methacrylate, dimethylaminoethyl methacrylate, dimethylaminoethyl methacrylate methyl chloride salt, diethylaminoethyl methacrylate, glycidyl methacrylate, tetrahydrofurfuryl methacrylate, allyl methacrylate , 2-Ethoxyethyl methacrylate, Eth Methacrylates such as lenglycol dimethacrylate, 1,3-butylene glycol dimethacrylate, 1,6-hexanediol dimethacrylate, trimethylolpropane trimethacrylate; allyl acrylate, n-butyl acrylate, i-butyl acrylate, t-butyl acrylate Acrylates such as 2-ethylhexyl acrylate, 2- (5-ethylpyridyl) ethyl acrylate, glycidyl acrylate, 2-cyanoethyl acrylate, ethylene glycol monoacrylate and propylene glycol monoacrylate; α such as methacrylic acid, acrylic acid and itaconic acid , Β unsaturated carboxylic acids; acrylamides such as acrylamide and N-methylol acrylamide;
[0016]
When the addition amount of the α, β unsaturated carboxylic acid monomer is too small, it becomes difficult to gel the thermoplastic resin composition more uniformly and to better combine the filler. Since the surface properties of the composite molded article obtained by excessively reducing the melt viscosity of the thermoplastic resin composition are deteriorated, the amount is preferably about 1 to 40 parts by weight with respect to 100 parts by weight of the thermoplastic resin.
[0017]
The polymerization initiator can exhibit the polymerization initiator function of the α, β unsaturated carboxylic acid monomer when the composite material containing the α, β unsaturated carboxylic acid monomer is heated and kneaded with an extruder. If it is not specifically limited, for example, polymerization initiators such as ketone peroxide-based, peroxyketal-based, dialkyl peroxide-based, diacyl peroxide-based, peroxydicarbonate-based, peroxyester-based It is done.
[0018]
The polymerization initiator preferably has a 10-hour half-life temperature of 60 ° C. or higher. When the temperature is less than 60 ° C., the polymerization reaction of the α, β unsaturated carboxylic acid monomer proceeds excessively, and the extrudability of the composite material may be deteriorated.
More preferably, the 10-hour half-life temperature is from 70 ° C. to 10 ° C. below the extrusion temperature.
[0019]
Some of these polymerization initiators are specifically listed below.
Tylacetoacetate peroxide, 1,1-bis (neohexylperoxy) -3,3,5-trimethylcyclohexane, 1,1-bis (neohexylperoxy) cyclohexane, 1,1-bis (t-butylperoxide Oxy) -3,3,5-trimethylcyclohexane, 1,1-bis (t-butylperoxy) cyclohexane, 1,1-bis (t-butylperoxy) cyclododecane, 2,2-bis (t-butyl) Peroxy) butane, n-butyl-4,4-bis (t-butylperoxy) valerate, 2,2-bis (4,4-di-t-butylperoxycyclohexyl) propane, di-t-butyl peroxide, Lauroyl peroxide, stearoyl peroxide, 2,4-dichlorobenzoyl peroxide, benzoyl peroxide T-butyl peroxybenzoate, 2,5-dimethyl-2,5-bis (benzoylperoxy) hexane, octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy 2-ethylhexano Ate, 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) hexane, 2,5-dimethyl-2,5-bis (m-toluoylperoxy) hexane, t-butylperoxy m-toluoylbenzoate, 1-cyclohexyl-1-methylethylperoxy 2-ethylhexanoate, neohexylperoxy 2-ethylhexanoate, t-butylperoxy 2-ethylhexanoate, t-butylper Oxy 3,5,5-trimethylhexanoate, t-butyl peroxyisobutyrate, t-butyl peroxy Oxylaurate, neohexyl peroxyisopropyl carbonate, t-butyl peroxyisopropyl carbonate, t-butyl peroxy 2-ethylhexyl carbonate, t-butyl peroxymaleate, t-butyl peroxyacetate, 2,4.4 -Trimethylpentyl 2 hydroxide etc. are mentioned.
[0020]
The selection of the α, β-unsaturated carboxylic acid monomer and the polymerization initiator and the blending ratio thereof are not particularly limited, but in each blending, a gel time tester (for example, Model No. 153) is used to measure the gel time under the same temperature condition as the extrusion temperature, and it is preferably prepared so that the gel time is 30 to 600 seconds.
[0021]
The composite material, if necessary, within a range not departing from the object of the present invention, reinforcing materials such as glass fibers and carbon fibers, plasticizers, lubricants, foaming agents, flame retardants, antioxidants, nucleating agents, A colorant such as a pigment may be added.
[0022]
Examples of the lubricant include hydrocarbon-based lubricants such as liquid paraffin, natural paraffin, microcrystalline wax, and polyethylene wax; higher fatty acid-based lubricants such as stearic acid; stearic acid amide, palmitic acid amide, methylene bisstearamide, Higher fatty acid amide lubricants such as ethylene bisstearamide; higher fatty acid ester lubricants such as butyl stearate, hydrogenated castor oil, ethylene glycol monostearate; higher aliphatic alcohol lubricants such as cetyl alcohol and stearyl alcohol; stearic acid Metal soaps such as zinc, calcium stearate, lead stearate and the like can be mentioned.
[0023]
Among the above lubricants, a lubricant having a high external lubricity such as a hydrocarbon-based lubricant, a higher fatty acid-based lubricant, and a metal soap is preferably used from the viewpoint of improving the moldability of a thermoplastic resin composition highly filled with a filler. It is done.
[0024]
If the addition amount of the lubricant is too small, the addition effect of imparting lubricity to the thermoplastic resin composition cannot be obtained sufficiently, and if too much, the kneadability of the thermoplastic resin composition is reduced or obtained. Since the physical property of the composite molded body to be obtained is lowered, it is preferably about 1 to 40 parts by weight relative to 100 parts by weight of the thermoplastic resin.
[0025]
The extruder used in the method for producing a thermoplastic resin molded article of the invention of the present invention is not particularly limited. For example, moisture or gas that has a vent port and adheres to a filler, a thermoplastic resin, or the like. It is preferable that the body can be separated and removed outside the extruder system, and a multi-screw extruder having two or more screws and excellent in kneadability is preferable.
[0026]
The screw shape, number of rotations, extrusion temperature, etc. will be described later, but there is an extruder that gives the thermoplastic resin a good performance as much as possible without giving excessive shear to the filler. Preferably used.
[0027]
The extruder used in the method for producing a thermoplastic resin molded body of the present invention is charged with a thermoplastic resin and a filler, and further an α, β unsaturated carboxylic acid monomer and a polymerization initiator. The means for charging the material components is not particularly limited, and for example, a method is adopted in which these composite materials are mixed and mixed into one inlet of the barrel on the screw base side while being mixed by a mixing device. However, the barrel of the screw root side is provided with a thermoplastic resin inlet, and on the downstream side, a filler, an α, β unsaturated carboxylic acid monomer and a polymerization initiator inlet are provided as side feeders, etc. A method may be employed in which they are provided via the input means and are input to these in the order described above. Depending on the type of filler, the order of introduction of the thermoplastic resin and filler may be reversed, and the α, β unsaturated carboxylic acid monomer and the polymerization initiator are mixed immediately before the addition, and the mixture of the above two. As a method, the method may be adopted.
[0028]
When using fillers such as wood powder with a high moisture content among the above-mentioned means for feeding thermoplastic resin and filler, etc., a method of feeding through a feeding means such as a side feeder, and forced by a vacuum pump from the vent port By using in combination with a venting method that degasses efficiently, the thermoplastic resin composition components can be efficiently degassed and dehydrated, and each thermoplastic resin composition component is homogeneously dispersed and beautifully gelled. It is possible to produce a thermoplastic resin molded article having a stable strength that is sufficiently gelled with surface properties.
[0029]
The outlet inner diameter of the adapter connecting the extruder and the molding die is much smaller than the barrel inner diameter of the extruder. When the resin passage is narrowed down, the resin pressure in the barrel of the extruder shows a sudden rise, and the thermoplasticity If molding of the resin molding becomes impossible and it is larger than the barrel inner diameter of the extruder, the residence time of the thermoplastic resin composition in the adapter becomes long and the quality of the thermoplastic resin molding obtained by burning etc. is remarkably lowered. Therefore, it is limited to 80 to 100% of the barrel inner diameter of the extruder.
[0030]
Between the adapter, the extruder, and the molding die, there is no provision of any resistor that blocks the passage of the thermoplastic resin composition other than the above-mentioned reduced diameter of the inner diameter of the adapter.
The resistor includes, for example, an adapter member including a breaker plate, a screen, and the like, and an adapter member that applies an excessive back pressure to a plasticized thermoplastic resin composition that is transferred from an extruder to a molding die. It refers to all members and parts.
[0031]
The form in which the adapter outlet inner diameter is set to 80 to 100% of the barrel inner diameter of the extruder is not particularly limited. For example, the resin flow is gently and linearly reduced at the same reduction rate from the adapter inlet to the outlet. Although the passage may be narrowed, a cylindrical portion having the same inner diameter connected to the throttle portion of the resin flow path may be provided near the outlet.
[0032]
As described above, the resin pressure in the barrel of the extruder is reduced by not providing any resistor that blocks the passage of the thermoplastic resin composition other than the reduction of the inner diameter of the adapter between the extruder and the molding die. A sharp rise causes a deterioration in the product quality such as burning of the thermoplastic resin composition, especially fillers such as wood flour, and rough skin, and in extreme cases, the extreme melt viscosity of the thermoplastic resin composition. It is possible to prevent the extrusion from becoming impossible due to such a decrease.
[0033]
Further, the thermoplastic resin composition is extruded by setting the barrel temperature at the tip of the extruder equipped as described above to a temperature not higher than the melting point of the thermoplastic resin.
If the barrel temperature at the tip of the extruder is too high, the thermoplastic resin composition highly filled with the filler will deteriorate the quality of the product obtained by burning or the like, and in the case of remarkable melting of the thermoplastic resin composition. Since extrusion becomes impossible due to an extremely low viscosity, it is preferably set at 15 ° C. or more lower than the melting point of the thermoplastic resin.
[0034]
The screw rotation speed of the extruder is determined by the screw design or the like and is not particularly limited, but if it is too small, a so-called vent-up phenomenon that the molten resin leaks from the vent port occurs, and if it is rotated too fast In addition, the thermoplastic resin composition highly filled with the filler deteriorates the quality of the product obtained by baking due to overheating or, in some cases, causes the impossibility of extrusion due to the extreme decrease in the melt viscosity of the thermoplastic resin composition. .
Therefore, the screw used is preferably a screw design that can achieve a high extrusion rate at a low rotational speed.
[0035]
The mold attached to the tip of the extruder has a structure in which a shaping mold and a cooling mold are directly connected, and the cooling mold is provided with a resin passage having substantially the same cross-sectional shape as the cross-sectional shape of the shaping mold discharge port. The resin passage inner peripheral surface serves as a cooling device.
[0036]
It is preferable that the ratio of the discharge port cross-sectional area to the resin inlet cross-sectional area of the shaping mold is in the range of 80 to 100%.
If the ratio is too small, the resin temperature rises abruptly due to an increase in the pressure inside the mold, and in particular, there is a risk that molding may become impossible due to an extreme decrease in the melt viscosity of the thermoplastic resin composition, If it exceeds 100%, a homogeneous thermoplastic resin molded product cannot be obtained.
[0037]
In addition, the cooling device for the cooling mold may be one that rapidly cools, but depending on the type of the thermoplastic resin composition, if necessary, with a gentle temperature gradient from the surface in contact with the shaping mold. A cooling zone having a plurality of stages of temperatures may be provided so as to be cooled.
[0038]
In the method for producing a thermoplastic resin molded article according to the first aspect of the present invention, as described above, the shaping mold and the cooling mold directly connected to the shaping mold are provided on the outlet side of the extruder body composed of the screw and the barrel. A method for producing a thermoplastic resin molded body that is solidified and extruded using a thermoplastic resin composition comprising a thermoplastic resin and a filler by an extrusion molding machine, wherein the outlet side of the extruder body and the shaping mold The adapter inner diameter is 80 to 100% of the barrel inner diameter of the extruder, and the adapter and the extruder During as well as The above adapter and shaping Mold of In the meantime, an adapter that is not provided with any resistor that blocks the passage of the thermoplastic resin composition other than the reduced diameter of the inner diameter of the adapter is used, and the barrel temperature near the outlet of the extruder body is the temperature of the thermoplastic resin. Since it is set to a temperature below the melting point and extruded, the thermoplastic resin composition is uniformly mixed in the resin flow path from the extruder to the molding die without sudden increase in resin pressure or resin temperature. Even if it is a bulky filler such as wood powder, it can be plasticized, so excessive shearing force is not applied, so the filler does not get damaged and its properties are made into a thermoplastic resin molded body. Addition, a characteristic composite material can be obtained, and in addition, it exhibits excellent extrusion performance during extrusion molding, excellent mechanical strength such as high bending strength, and excellent thermoplastic resin molding with a smooth and beautiful appearance Getting a body It can be.
[0039]
As described above, the method for producing a thermoplastic resin molded article according to claim 2 is the method for producing a thermoplastic resin molded article according to claim 1, wherein the shaping mold is used. Is Resin inlet cross-sectional area do it, Cross-sectional area of resin flow path in shaping mold and Of the above shaping mold Since the ratio of the discharge port cross-sectional area is in the range of 80 to 100%, in the molding die, the thermoplastic resin composition that is uniformly mixed and thermoplasticized without the resin pressure and the resin temperature rising rapidly, Even if it contains a bulky filler such as wood flour, it can be shaped uniformly and has excellent mechanical strength such as high bending strength and excellent thermoplasticity with a smooth appearance and beauty A resin molded body can be obtained.
[0040]
As described above, the method for producing a thermoplastic resin molded article according to the third aspect of the present invention is the method for producing a thermoplastic resin molded article according to the first or second aspect, wherein the heat comprising the thermoplastic resin and the filler is used. Since the α, β-unsaturated carboxylic acid monomer and the polymerization initiator are further added to the plastic resin composition, the composite material composition can be obtained with extremely large plasticizing power of the α, β-unsaturated carboxylic acid monomer. The product can be quickly and uniformly plasticized and kneaded, and further, it is polymerized and resinized by heating in the extruder, and is uniformly dispersed in the composite composition, so it has good extrusion performance. The obtained thermoplastic resin molded product can provide an excellent composite molded product having excellent mechanical strength such as high bending strength and a beautiful appearance with a smooth appearance.
[0041]
The method for producing a thermoplastic resin molded article according to claim 4 is the method for producing a thermoplastic resin molded article according to claim 1, 2 or 3, wherein the thermoplastic resin is a polyolefin resin. Since the filler is wood flour, the moldability is usually significantly reduced by foaming or other abnormal extrusion during extrusion, and the resulting composite molded article has various physical properties, especially foaming. Although the surface performance such as surface roughness is remarkably deteriorated, the method for producing the thermoplastic resin molded body of the present invention has excellent mechanical strength such as high bending strength, and excellent thermoplastic resin with a smooth appearance and a beautiful appearance. A molded body can be obtained with high productivity.
[0042]
DETAILED DESCRIPTION OF THE INVENTION
Examples of the present invention will be described in detail below. However, the present invention is not limited to these examples.
[0043]
FIG. 1 is an explanatory view showing an example of an apparatus used in the method for producing a thermoplastic resin molded article of the present invention. An extruder 1 is a twin-screw co-directional extruder with a screw 2 mounted in a barrel 3. (With a diameter of 44 mmφ), on the upper surface of the barrel 3, a thermoplastic resin inlet 4 on the screw root side, a liquid additive (α, β unsaturated carboxylic acid monomer and polymerization initiator) inlet 6, side A filler inlet 5 and a vent 7 for discharging moisture and other gas bodies released from these thermoplastic resin compositions through an feeder such as a feeder are provided in the above order.
[0044]
A molding die is attached to the tip of the extruder 1. The molding die has a cross-sectional area of the resin inlet of 12 cm ² And a sheet shaping die 8 having a cross section of 5 mm × 277 mm in cross section and a resin passage having the same cross sectional shape as the cross section of the shaping die 8 are provided, and the inner peripheral surface of the resin passage is cooled. The cooling mold 9 as an apparatus is directly connected in the illustrated order.
Further, the adapter 10 outlet inner diameter for mounting the molding die on the tip of the extruder 1 is 42 mmφ, and the resin flow path is gently and gently narrowed from the tip of the extruder 1 to the molding die resin inlet. It is what has.
[0045]
Although the above-mentioned shaping mold has a very simple structure and is not shown in the figure, if an example is shown, the ratio of the discharge port cross-sectional area to the resin inlet cross-sectional area of the shaping mold is 100%, Except for providing an inclination of the resin flow, all the cross-sectional areas from the resin inflow port to the discharge port of the shaping mold do not increase or decrease and are substantially the same.
[0046]
(Example 1)
Using the extrusion molding machine shown in FIG. 1, the temperature is increased from the screw root, the temperature of the plasticizing zone is set to 180 ° C., the temperature of the screw tip is set to 150 ° C., and the screw rotation speed is set to 90 rpm. It was.
As a thermoplastic resin, 100 parts by weight of polypropylene (manufactured by Nippon Polychem Co., Ltd., trade name “Novatech MA-3”, melting point 165 ° C.) is introduced through the inlet 4 and then 200 parts by weight of wood flour (45 mesh) as a filler. Was introduced from the inlet 5 through the side feeder.
[0047]
The charged composite material composition is heated and mixed in the extruder 1 and is subjected to a molding die at an extrusion rate of 65 kg / hour while being vacuum degassed from the vent port 7 provided on the tip side from the input ports 4 and 5. From this, it was solidified and extruded to produce a thermoplastic resin sheet. At this time, the resin temperature in the shaping die 8 of the molding die was 182 ° C.
[0048]
The obtained thermoplastic resin sheet was hardly burned in the filled wood powder, had a beautiful appearance with no burning discoloration accompanying this, and a homogeneous structure, and its bending strength was 36 MPa. .
[0049]
(Example 2)
The same thermoplastic resin and filler as in Example 1 were charged using the same extrusion temperature conditions as in Example 1, and 10 parts by weight of cyclohexyl methacrylate as an α, β unsaturated carboxylic acid monomer. As a polymerization initiator, 0.5 part by weight of cumene hydroperoxide was mixed and injected from the inlet 6 between the thermoplastic resin inlet 4 and the filler inlet 5, and the extrusion rate was 65 kg / hour. A thermoplastic resin sheet was produced by solidifying and extruding from a molding die. At this time, the resin temperature in the shaping die 8 of the molding die was 176 ° C.
[0050]
The obtained thermoplastic resin sheet was hardly burned in the filled wood powder, had a beautiful appearance with no burning discoloration and a homogeneous structure, and its bending strength was 35 MPa. .
[0051]
(Comparative Example 1)
A thermoplastic resin sheet was produced in the same manner as in Example 1 except that instead of the adapter used in Example 1, an adapter having an adapter outlet inner diameter of 26 mmφ that was linearly abruptly narrowed down was used.
The amount of extrusion is 30 kg / hour, the resin temperature in the shaping die 8 of the molding die at this time exceeds 200 ° C., and the obtained thermoplastic resin sheet is burnt with wood powder and looks generally burnt. The appearance was not distorted, the structure was non-uniform, and the bending strength was 20 MPa.
[0052]
(Comparative Example 2)
A thermoplastic resin sheet was produced in the same manner as in Example 1 except that the same extruder as in Example 1 was used, the screw speed was changed to 100 rpm, and the set temperature at the screw tip was changed to 180 ° C.
The amount of extrusion is 30 kg / hour, the resin temperature in the shaping die 8 of the molding die at this time exceeds 200 ° C., and the obtained thermoplastic resin sheet is burnt with wood powder and looks generally burnt. The appearance was not distorted, the structure was non-uniform, and the bending strength was 20 MPa.
[0053]
【The invention's effect】
The method for producing a thermoplastic resin molded article according to the first aspect of the present invention is configured as described above, and thus exhibits excellent extrusion performance, excellent mechanical strength such as high bending strength, and smooth appearance. A beautiful and excellent composite molded body can be obtained with high productivity.
[0054]
Since the method for producing a thermoplastic resin molded article according to the second aspect of the present invention is configured as described above, a high bending strength or the like can be obtained by the flow of the homogeneous thermoplastic resin composition in the shaping mold. An excellent composite molded body having excellent mechanical strength and a smooth appearance can be obtained with high productivity.
[0055]
Since the method for producing a thermoplastic resin molded article according to the third aspect of the present invention is configured as described above, the thermoplastic resin composition can be rapidly and uniformly plasticized and kneaded. It is possible to obtain an excellent thermoplastic resin molded article that exhibits extrusion performance, has excellent mechanical strength such as high bending strength, and has a smooth external appearance and high productivity.
[0056]
Since the method for producing a thermoplastic resin molded article according to the invention of claim 4 is configured as described above, it is excellent in high bending strength and the like from a composite material composed of polyolefin containing a large amount of wood flour. Therefore, it is possible to obtain a composite pellet with high productivity, which can obtain an excellent composite molded body having excellent mechanical strength and smooth appearance.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an example of an apparatus used in a method for producing a thermoplastic resin molded body of the present invention.
[Explanation of symbols]
1 Extruder
2 screw
3 barrels
4 Raw material inlet
5 Raw material inlet (with side feeder)
6 Liquid additive pressure inlet
7 Vent port
8 Molding mold
9 Cooling mold
10 Adapter

Claims (4)

Solidified using a thermoplastic resin composition consisting of a thermoplastic resin and a filler by an extrusion molding machine provided with a shaping mold and a cooling mold directly connected to it on the outlet side of the extruder body consisting of a screw and a barrel. A method for producing a thermoplastic resin molded body to be extruded, wherein an inner diameter of an outlet side of an adapter provided between the outlet side of the extruder body and the shaping mold is 80 to 100% of a barrel inner diameter of the extruder. There between the adapter and the extruder and between the adapter and the shaping mold shrinkage diameter or outside of the inner diameter of the adapter, also without providing any resistor blocks the passage thermoplastic resin composition, and, extruding A method for producing a thermoplastic resin molded article, characterized in that the barrel temperature near the outlet of the machine body is set to a temperature not higher than the melting point of the thermoplastic resin and extruded. The shaping mold, and against the resin flow inlet cross-sectional area, the ratio of the cross-sectional area and the discharge port cross-sectional area of the shaping mold of the shaping mold in the resin flow path is in the range of 80% to 100% The manufacturing method of the thermoplastic resin molding of Claim 1. The method for producing a thermoplastic resin molded article according to claim 1 or 2, wherein an α, β unsaturated carboxylic acid monomer and a polymerization initiator are further added to a thermoplastic resin composition comprising a thermoplastic resin and a filler. The method for producing a thermoplastic resin molded article according to claim 1, 2 or 3, wherein the thermoplastic resin is a polyolefin resin and the filler is wood flour.

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