JP5742177B2 - Wood resin molding - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a wood resin composition comprising a wood resin composition containing a thermoplastic resin and wood powder and a polycarbonate resin having a specific structure.

  Since wood is a so-called carbon-neutral resource that can be repeatedly produced by photosynthesis, many attempts have been made to cultivate forests with fast-growing tree species and use them as industrial materials with low environmental impact. For example, a molded body made using a woody resin composition made by mixing thermoplastic resin and wood powder has an appearance and texture similar to wood and is widely used as a building material with excellent moldability. I came.

  In the past, a wood resin molded body has been proposed in which a polyvinyl chloride resin and wood powder are the main components and a reinforcing filler such as glass fiber and a modifier such as ABS resin are added. However, since materials using vinyl chloride resin require acid-resistant incineration equipment when incinerating wastes from the processing and dismantling of scraps, the separation and treatment process is very time-consuming. Environmental impacts could not be overlooked because of the exhaust of gas.

  Since then, many studies have been conducted to replace vinyl chloride resins with styrene resins and polyolefin resins, and the use of resins with specific viscosities, modified resins, and addition of various fillers has been proposed. It was. Polyolefin resins are currently used exclusively for wood resin moldings, but these thermoplastic resins have insufficient weather resistance, and degradation such as yellowing and embrittlement is a problem in applications that have been installed outdoors for many years. There was.

  In order to solve the problem of the weather resistance of the wood resin molded article, the present applicant has added an ultraviolet absorber to the wood resin composition itself containing a thermoplastic resin such as a styrene resin as a main component. Studies have been made such as providing a coating layer made of an acrylic resin or the like to which weather resistance has been added to the surface of the base material made of the woody resin composition (for example, see Patent Documents 1 to 4).

JP 2000-6316 A Japanese Patent Laid-Open No. 2000-7880 JP 2000-239432 A JP 2000-239466 A

  However, when an ultraviolet absorber is added to the woody resin composition, it is necessary to add the ultraviolet absorber in a large amount because the additive needs to be dispersed throughout the molded product, and the cost increase cannot be overlooked. On the other hand, when a coating layer made of an acrylic resin or the like to which an ultraviolet absorber is added is provided on the surface of the wood resin molded article base, the acrylic resin is not sufficiently heat resistant. There was room for improvement in terms of the possibility of softening, deformation and peeling.

  That is, an object of the present invention is to provide a woody resin molded article having excellent weather resistance and excellent heat resistance regardless of the presence or absence of an ultraviolet absorber.

  As a result of intensive studies, the present inventors have found that the above-mentioned problem is a wood resin molded article in which a coating layer mainly composed of a polycarbonate resin having a specific structure is provided on the surface of a base material made of a wood resin composition. As a result, it was found that all of the above could be solved, and the present invention was completed.

  According to the first invention, a dihydroxy compound having a portion represented by the following formula (1) as a part of the structure on the surface of a base material composed of a woody resin composition containing a thermoplastic resin and wood flour. There is provided a woody resin molded article provided with a coating layer mainly composed of a polycarbonate resin containing a derived structural unit.

(However, moiety represented by the formula (1) unless it is part of _-CH 2 -O-H.)

  According to a second invention, in the first invention, the dihydroxy compound is a dihydroxy compound represented by the following formula (2).

  According to a third invention, in the first or second invention, an ultraviolet absorber is added in a range of 0.0001% by mass to 10% by mass with respect to 100% by mass of the total resin constituting the coating layer. It is characterized by.

  ADVANTAGE OF THE INVENTION According to this invention, the wooden resin molding excellent in a weather resistance and heat resistance is provided, and can be used suitably for structural members, such as a flooring for construction, a wall material, a wood deck, a bench, a table.

  Hereinafter, a woody resin molded body as an example of an embodiment of the present invention will be described. However, the scope of the present invention is not limited to the embodiments described below.

  In the present invention, the “main component” means that the ratio of the target component in the part is 50% by mass or more, preferably 75% by mass or more and 100% by mass or less.

<Base material>
The base material which comprises the woody resin molding of this invention consists of a woody resin composition containing a thermoplastic resin and wood flour.

[Thermoplastic resin]
The type of thermoplastic resin that can be used in the wood resin composition is not particularly limited, and a resin that can provide performance that is considered for each application, such as heat resistance, rigidity, impact resistance, and flame resistance, should be selected. That's fine. Specifically, rubber reinforced styrene resin such as polyvinyl chloride resin, polyolefin resin, ABS resin, polycarbonate resin, polyester resin, polyphenylene ether resin (including styrene-modified polyphenylene ether resin) and the like can be suitably used. These may be used alone or in combination of two or more.
Among them, weather resistance and heat resistance can be obtained by adopting a polycarbonate resin containing a structural unit derived from a dihydroxy compound having a site represented by the formula (1) in a part of the structure, which is also used for the coating layer in the present invention. In addition to the above, it is possible to obtain a wood resin molded article excellent in the adhesion between the base material and the coating layer, and to improve the weight ratio (so-called biomass degree) derived from a biogenic substance to reduce the environmental load. This is preferable because it is possible.

[Wood flour]
There is no restriction | limiting in particular as a kind of wood flour which can be used for the said woody resin composition, Various wood flour can be used. For example, pine trees such as spruce, larch, todomatsu, and wood flour such as persimmon, cherry, cedar, persimmon, persimmon, beech, lawan and persimmon can be used. The shape is preferably a pulverized product, and a pulverized product selected with a sieve having an opening of 150 μm or less is particularly suitable for the fineness of the wood texture.

The content of the wood flour in the wood resin composition is not particularly limited, but is preferably in the range of 30% by mass to 300% by mass with respect to 100% by mass of the thermoplastic resin, 30% by mass or more, A range of 200% by mass or less is particularly preferable. A wood powder content of 30% by mass or more is preferable because a sufficient wood texture can be obtained. On the other hand, a wood powder content of 300% by mass or less is preferable because sufficient formability can be secured.
In addition, when it is necessary to improve the moldability even if it is 300% by mass or less, in the molten state of the woody resin composition by adding a lubricant, a wax resin or the like, or covering the wood powder with a modified resin What is necessary is just to devise to improve fluidity.

[Foaming agent]
A foaming agent can be added to the wood resin composition as necessary. The foaming agent that can be used and the amount of addition thereof are not particularly limited and can be appropriately selected depending on the foaming ratio and the molding method. For example, organic thermal decomposition type foaming agents such as azodicarbonamide (ADCA), inorganic thermal decomposition type foaming agents such as sodium hydrogen carbonate, and mixtures thereof can be used.
The wood resin molded body using the wood resin composition to which a foaming agent is added as a base material can reduce the weight of the product plate material by foaming at the time of molding, and can simplify the housing supported at the bottom. It is preferable because the work load when assembling and constructing a wood terrace can be reduced.

[Other ingredients]
In addition to the wood resin composition, as other components, a heat stabilizer, a light stabilizer, various additives such as a colorant, and the like are added as long as the characteristics of the present invention such as weather resistance and heat resistance are not impaired. Also good.

[Manufacturing method of substrate]
The method for producing the substrate in the present invention can be selected according to the target form and is not particularly limited.
For example, the thermoplastic resin, the wood flour, and other additives are dry blended with respect to the content in the range described in the present specification, and these are put into a single screw extruder, a twin screw extruder, or the like. It can be obtained by charging, melt-kneading and adopting the molding method described later.
In addition, a master batch pellet is prepared by melting and kneading a larger amount of the wood flour, and other additives, etc. with respect to the thermoplastic resin, and then appropriately diluting them with the thermoplastic resin. It can also be obtained by melt-kneading again and adopting the molding method described later while adjusting the content to be in the range described in this specification.
In addition, for example, when the above-mentioned foaming agent is added, depending on the type of foaming agent, foaming may occur during the production of the masterbatch. Therefore, it is preferable to form the substrate by the above-mentioned dry blending.
The temperature of the extruder and die when melt-kneading is not particularly limited as long as it is in a range suitable for the thermoplastic resin.

The method for molding the substrate in the present invention is not particularly limited, and various molding methods can be employed depending on the shape of the target molded body. For example, if the shape is film, sheet, plate, etc., extrusion molding (T-die casting method, etc.) or calendar molding can be adopted, and if it is other specific three-dimensional shape, profile extrusion molding or injection molding. Etc. can be adopted. Further, a base material having a target shape can be obtained by performing secondary processing such as thermoforming, vacuum forming, pressure forming, and cutting.
Moreover, when adding a foaming agent as mentioned above, the base material as a target foaming molding can be obtained by shape | molding at predetermined | prescribed temperature.

<Coating layer>
[Polycarbonate resin]
The polycarbonate resin used for the coating layer of the present invention is a polycarbonate resin containing a structural unit derived from a dihydroxy compound having a site represented by the following formula (1) in a part of the structure.

(However, moiety represented by the formula (1) unless it is part of _-CH 2 -O-H.)
That is, the dihydroxy compound refers to a compound containing at least two hydroxyl groups and at least a site represented by general formula (1).

The main component of the dihydroxy compound having a site represented by the formula (1) in a part of the structure is not particularly limited as long as it has a structure represented by the formula (1) in the molecule. Specifically, 9,9-bis (4- (2-hydroxyethoxy) phenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-methylphenyl) fluorene, 9,9 -Bis (4- (2-hydroxyethoxy) -3-isopropylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-isobutylphenyl) fluorene, 9,9-bis (4- ( 2-hydroxyethoxy) -3-tert-butylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3-cyclohexylphenyl) fluorene, 9,9-bis ( -(2-hydroxyethoxy) -3-phenylphenyl) fluorene, 9,9-bis (4- (2-hydroxyethoxy) -3,5-dimethylphenyl) fluorene, 9,9-bis (4- (2- Hydroxyethoxy) -3-tert-butyl-6-methylphenyl) fluorene 9,9-bis (4- (3-hydroxy-2,2-dimethylpropoxy) phenyl) fluorene, etc., having an aromatic group in the side chain A cyclic ether structure represented by a compound having an ether group bonded to an aromatic group in the main chain, a dihydroxy compound represented by the following formula (2), and a spiroglycol represented by the following formula (3) A dihydroxy compound is mentioned. Among these, a dihydroxy compound having a cyclic ether structure is preferable, and among the dihydroxy compounds having a cyclic ether structure, an anhydrous sugar alcohol represented by the formula (2) is particularly preferable. More specifically, examples of the dihydroxy compound represented by the formula (2) include isosorbide, isomannide, and isoide which are in a stereoisomeric relationship. Moreover, as a dihydroxy compound represented by the following formula (3), 3,9-bis (1,1-dimethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro (5.5) Undecane (common name: spiroglycol), 3,9-bis (1,1-diethyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane, 3,9-bis (1,1-dipropyl-2-hydroxyethyl) -2,4,8,10-tetraoxaspiro (5.5) undecane and the like.
These may be used alone or in combination of two or more.

(Wherein R _{1 to} R ₄ are each independently an alkyl group having 1 to 3 carbon atoms.)

  The dihydroxy compound represented by the formula (2) is an ether diol that can be produced from a saccharide using a biogenic material as a raw material. In particular, isosorbide can be produced at low cost by hydrogenating and dehydrating D-glucose obtained from starch, and can be obtained in abundant resources. For these reasons, isosorbide is most preferably used.

  The polycarbonate resin used in the present invention may further contain a structural unit other than the structural unit represented by the formula (1). For example, the structural unit is derived from an aliphatic dihydroxy compound described in WO 2004/111106. And structural units derived from alicyclic dihydroxy compounds described in International Publication No. 2007/148604 pamphlet.

  Among the structural units derived from the aliphatic dihydroxy compound, at least one selected from ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol. It is preferable to include a structural unit derived from the dihydroxy compound.

Among the structural units derived from the alicyclic dihydroxy compound, it is preferable to include a 5-membered ring structure or a 6-membered ring structure. In particular, the 6-membered ring structure may be fixed to a chair type or a boat type by a covalent bond. By including a structural unit derived from the alicyclic dihydroxy compound having these structures, the heat resistance of the obtained polycarbonate resin can be enhanced. The number of carbon atoms contained in the alicyclic dihydroxy compound is usually 70 or less, preferably 50 or less, more preferably 30.
It is as follows.

Examples of the alicyclic dihydroxy compound containing the 5-membered ring structure or the 6-membered ring structure include those described in the pamphlet. Among them, cyclohexanedimethanol, tricyclodecanedimethanol, adamantanediol, and pentacyclopentadecanedimethanol are among others. Further, cyclohexane dimethanol or tricyclodecane dimethanol is most preferable in view of economy and heat resistance. These may be used alone or in combination of two or more.
Of the cyclohexanedimethanol, 1,4-cyclohexanedimethanol, which is industrially easily available, is preferred.

  The content ratio of the structural unit derived from the dihydroxy compound having a site represented by the formula (1) in a part of the structure of the polycarbonate resin used in the present invention is preferably 30 mol% or more, more preferably 50 mol%. Or more, preferably 90 mol% or less, more preferably 80 mol% or less. By setting it as such a range, coloring due to the carbonate structure, coloring due to impurities contained in a trace amount due to the use of a biological resource substance, etc. can be suppressed, and it can be sufficiently used as a polycarbonate resin having visible light permeability. it can. In addition, it is difficult to achieve with a polycarbonate resin composed of only a structural unit derived from a dihydroxy compound having a site represented by the formula (1) in a part of the structure. It is possible to balance physical properties such as.

  The polycarbonate resin used in the present invention is a structural unit derived from a dihydroxy compound having a site represented by the formula (1) in a part of its structure, a structural unit derived from an aliphatic dihydroxy compound, or an alicyclic dihydroxy compound. It is preferable that the structural unit is derived from the above, but a structural unit derived from another dihydroxy compound may be included as long as the object of the present invention is not impaired.

  The glass transition temperature of the polycarbonate resin used in the present invention is measured by differential scanning calorimetry (DSC) and is usually 45 ° C. or higher and 155 ° C. or lower, preferably 95 ° C. or higher and 155 ° C. or lower, more preferably 105 ° C. or higher and 155 ° C. or lower. And usually has a single glass transition temperature. When the glass transition temperature is in such a range, sufficient heat resistance for using the woody resin molded product of the present invention outdoors over a long period of time can be obtained. By appropriately adjusting the polymerization composition ratio of the polycarbonate resin, it is possible to adjust the glass transition temperature within such a range.

  The polycarbonate resin used in the present invention can be produced by a generally used polymerization method, and may be either a phosgene method or a transesterification method in which it is reacted with a carbonic acid diester. Among these, a transesterification method in which a dihydroxy compound having a site represented by the formula (1) in a part of the structure and another dihydroxy compound in the presence of a polymerization catalyst is reacted with a carbonic acid diester is preferable. The transesterification method is a polymerization method in which a dihydroxy compound, a carbonic acid diester, a basic catalyst, and an acidic substance that neutralizes the catalyst are mixed to perform a transesterification reaction.

Examples of the carbonic acid diester include diphenyl carbonate, ditolyl carbonate, bis (chlorophenyl) carbonate, m-cresyl carbonate, dinaphthyl carbonate, bis (biphenyl) carbonate, diethyl carbonate, dimethyl carbonate, dibutyl carbonate, and dicyclohexyl carbonate. Diphenyl carbonate is preferably used.
The molecular weight of the polycarbonate resin containing the structural unit derived from the dihydroxy compound having the site represented by the formula (1) in a part of the structure used in the present invention thus obtained can be expressed by reduced viscosity. The reduced viscosity is usually 0.30 dL / g or more, preferably 0.35 dL / g or more, and the upper limit of the reduced viscosity is more preferably 1.20 dL / g or less, more preferably 1.00 dL / g or less. 80 dL / g or less is more preferable. If the reduced viscosity of the polycarbonate resin is too low, the mechanical strength of the molded product may be small. If it is too large, the fluidity at the time of molding tends to decrease, and the productivity and moldability tend to decrease.
The reduced viscosity is measured using a Ubbelohde viscometer at a temperature of 20.0 ° C. ± 0.1 ° C., using methylene chloride as a solvent and precisely preparing a polycarbonate concentration of 0.6 g / dL.

The polycarbonate resin used in the present invention has low light absorption in the visible light to near-ultraviolet wavelength region, and excellent weather resistance with respect to yellowing deterioration due to light reception. Therefore, an ultraviolet absorber for suppressing the yellowing deterioration of the resin itself is used. Even if used, the amount can be significantly reduced. In the case where measures against yellowing deterioration are required, such as containing other resins other than the polycarbonate resin used in the present invention, a minimum necessary ultraviolet absorber for suppressing this may be added.
In this case, it is preferable that the addition amount of the ultraviolet absorber with respect to 100% by mass of the total resin constituting the coating layer in the present invention is in the range of 0.0001 to 10% by mass. Moreover, it is more preferable to use it in the ratio of 0.0005 mass% or more and 1 mass% or less, It is further more preferable to mix | blend in the ratio of 0.001 mass% or more and 0.5 mass% or less, 0.01 mass It is particularly preferable to blend at a ratio of not less than% and not more than 0.2% by mass. If it is 0.0001% by mass or more, the ultraviolet absorption performance can be sufficiently exhibited, and if it is 10% by mass or less, the coloring of the resin can be suppressed or the raw material cost can be reduced. . Furthermore, by adjusting the amount of the ultraviolet absorbent in such a range, without causing the bleeding out of the ultraviolet absorbent on the surface of the wood resin molded body of the present invention and the deterioration of the mechanical properties of the wood resin molded body of the present invention, The weather resistance of the woody resin molded product of the present invention can be improved.

[Ultraviolet absorber]
Various commercially available ultraviolet absorbers can be used as necessary for the polycarbonate resin used in the present invention, but those used exclusively for addition to conventionally known aromatic polycarbonate resins can be suitably used. . Examples include 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (3-tert-butyl-5-methyl-2-hydroxyphenyl) -5-chlorobenzotriazole, 2 -(5-methyl-2-hydroxyphenyl) benzotriazole, 2- [2-hydroxy-3,5-bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, 2,2′-methylenebis (4 Benzotriazole ultraviolet absorbers such as -cumyl-6-benzotriazolephenyl), benzoxazine ultraviolet absorbers such as 2,2'-p-phenylenebis (1,3-benzoxazin-4-one), 2- Such as (4,6-diphenyl-1,3,5-triazin-2-yl) -5- (hexyl) oxy-phenol B hydroxyphenyl triazine-based ultraviolet absorbers. The melting point of the ultraviolet absorber is particularly preferably in the range of 120 to 250 ° C. When an ultraviolet absorber having a melting point of 120 ° C. or higher is used, fogging due to gas on the surface of the molded article is reduced and improved.
More specifically, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole 2- [2'-hydroxy-3 '-(3 ", 4", 5 ", 6" -tetrahydrophthalimidomethyl) -5'-methylphenyl] benzotriazole, 2,2-methylenebis [4- (1, 1,3,3-tetramethylbutyl) -6- (2H-benzotriazole-2
-Yl) phenol, benzotriazole ultraviolet absorbers such as 2- (2-hydroxy-3,5-dicumylphenyl) benzotriazole, and 2- (4,6-diphenyl-1,3,5-triazine-2- Yl) -5- (hexyl) oxy-phenol and other hydroxyphenyl triazine-based UV absorbers are used. Among these, 2- (2-hydroxy-3,5-dicumylphenyl) benzotriazole, 2 , 2-methylenebis [4- (1,1,3,3-tetramethylbutyl) -6- (2H-benzotriazol-2-yl) phenol, 2- (4,6-diphenyl-1,3,5- Triazin-2-yl) -5- (hexyl) oxy-phenol is preferred. These ultraviolet absorbers may be used alone or in combination of two or more.

[Other ingredients]
In the coating layer in the present invention, as other components, a thermoplastic resin other than the polycarbonate resin used in the present invention, a heat stabilizer, a light stabilizer, various additives such as a colorant, weather resistance, heat resistance, etc. You may add in the range which does not impair the characteristic of this invention.

  The thickness of the coating layer in the present invention is preferably in the range of 20 μm to 200 μm, and more preferably in the range of 50 μm to 150 μm. A thickness of 20 μm or more is preferable because the ultraviolet absorption capability is sufficient, and problems such as peeling of the coating layer hardly occur. On the other hand, if it is 200 micrometers or less, since the wood texture of the woody resin molding of this invention is not impaired, it is preferable.

  Further, the coating layer in the present invention may be a single layer as long as it is a layer mainly composed of the polycarbonate resin, but a plurality of layers composed mainly of the polycarbonate resin whose composition is changed within the range described in this specification. And it can also be set as a coating layer in all the layers.

<Wood resin molding>
The woody resin molded product of the present invention is obtained by providing the coating layer on the surface of the substrate.
The method for providing the coating layer on the surface of the base material is not particularly limited, but it can be provided by, for example, heat fusion or via an adhesive layer. At this time, it is preferable to provide by heat fusion because a coating layer having better weather resistance can be provided.

  In addition, the coating part of the coating layer on the surface of the base material may be the whole base material, or may be coated so as to protect only the part exposed to solar radiation or rain, and is appropriately selected for each application. .

  When the coating layer is provided on the surface of the base material by heat fusion, for example, the wood resin composition constituting the base material and the resin constituting the coating layer are co-extruded to perform molding and coating simultaneously. A method or a method of producing a sheet by extrusion molding or calendar molding using a resin constituting the coating layer, laminating the sheet on a previously molded base material, and coating by thermal lamination molding can be employed.

  Moreover, when providing the said coating layer on the surface of the said base material through an adhesive layer, the said wooden resin composition which comprises the said base material, the adhesive material which comprises an adhesive layer, and resin which comprises a coating layer A co-extrusion method is used to perform molding and coating simultaneously, or an adhesive layer is provided on the surface of a preformed substrate by various methods, and the sheets used for the coating layer are laminated and coated by thermal lamination molding. A method etc. can be adopted.

[Adhesive layer]
The adhesive material that can be used for the adhesive layer is not particularly limited as long as the weather resistance and heat resistance, which are the characteristics of the present invention, are not impaired, and the substrate and the coating layer are firmly adhered to each other. Such a material can be appropriately selected and used. Further, a small amount of the ultraviolet absorber as described above may be added to the adhesive layer in order to improve the weather resistance.

  The woody resin molded body of the present invention is excellent in weather resistance because the polycarbonate resin is used for the coating layer, and 500 hours have passed in a weather resistance test with a sunshine weather meter conducted under a black panel temperature of 63 ° C. Even after, yellowing deterioration and peeling do not occur.

  The woody resin molded body of the present invention is excellent in heat resistance. For example, when it is installed outdoors as a wood deck, it does not leave a mark even if a heavy object such as a table or bench is placed. . Moreover, even if immersed in boiling water, it does not soften or deform.

  Since the woody resin molded body of the present invention is excellent in weather resistance and heat resistance, it can be suitably used for structural members such as building floors and walls in houses and the like, wood decks, benches, and tables indoors and outdoors.

  In order to describe the present invention more specifically and in detail, examples are shown below, but the present invention is not limited to these examples.

<Base material>
The following were used as materials constituting the base material: (a-1): As a thermoplastic resin, lead-based hard vinyl chloride resin (b-1): As wood flour, trade name “Cellulosin # 100” manufactured by Casino Corporation
(C-1): Trade name “Sanol LS770” manufactured by Sanyo Chemical Industries, Ltd. as an organophosphorus antioxidant.
(C-2): Commercially available brown pigment as a colorant.

<Coating layer>
The following materials were used as the material constituting the coating layer.
(D-1): Using isosorbide as a dihydroxy compound and 1,4-cyclohexanedimethanol, a structural unit derived from isosorbide: a structural unit derived from 1,4-cyclohexanedimethanol = 70: 30 (mol%) A polycarbonate resin having a reduced viscosity of 0.51 dl / g obtained by a melt polymerization method.
(D-2): “Acrypet VH5” manufactured by Mitsubishi Rayon Co., which is a polymethyl methacrylate resin.
(D-3): “NOVAREX 7025A” manufactured by Mitsubishi Engineering Plastics, which is an aromatic polycarbonate resin.
(E-1): As a UV absorber, trade name “TINUVIN 1577FF” manufactured by BASF Corporation.
(E-2): Trade name “Tinuvin 326” manufactured by BASF as an ultraviolet absorber.

<Production of wood resin molding>
(A-1) 50% by mass, (b-1) 50% by mass, (c-1) 0.5% by mass, (c-2) 3% by mass of the material constituting the base material, It was melt-kneaded with a twin screw extruder to obtain pellets for a substrate. Subsequently, the material which comprises a coating layer was mix | blended with the ratio of Table 1, and it knead | mixed and kneaded with the twin-screw extruder, and obtained the pellet for coating layers. These were melted using two single-screw extruders, co-extruded using a multi-manifold die so that the thickness of the substrate was 3 mm and the thickness of the coating layer was 80 μm, and two types of two-layer plates A woody resin molded product was obtained.

<Evaluation>
(1) Weather resistance In the weather resistance test with a sunshine weather meter under the condition of a black panel temperature of 63 ° C., the appearance of the produced wood resin molded product was visually observed and judged according to the following criteria.
○: No yellowing deterioration or peeling.
Δ: Slight yellowing deterioration is observed.
X: Deterioration markedly yellowing and peeling may be observed.

(2) Wood texture The appearance of the obtained wood resin molding was visually observed and judged according to the following criteria.
○: The wood texture is very excellent.
Δ: Wood texture.
X: There is no wood texture.

(3) Heat resistance About the resin composition which comprises the coating layer used by the Example and the comparative example, a glass transition temperature is measured by differential scanning calorimetry (DSC) based on JISK7121, and it is 105 degreeC or more. Was evaluated as ◯, and a value of less than 105 ° C. as x.

(4) Biomass degree The weight ratio (biomass degree) derived from a biogenic substance was calculated about the resin component used for the resin composition which comprises the coating layer used by the Example and the comparative example, and it determined with the following references | standards.
○: 40% by mass or more Δ: 25% by mass or more and less than 40% by mass ×: less than 25% by mass

As is apparent from Table 2, the examples in which the woody resin moldings of the present invention were produced were excellent in both weather resistance and heat resistance, and had sufficient wood texture and biomass.
On the other hand, in Comparative Example 1 in which an acrylic resin is used for the coating layer, the heat resistance is insufficient. Moreover, in Comparative Example 2 using an aromatic polycarbonate resin for the coating layer, the weather resistance is insufficient, and even if the amount of the ultraviolet absorber is increased as in Comparative Example 3, the weather resistance is still insufficient, and Since the color tone of the coating layer changed due to yellowing or an increase in the amount of the UV absorber, the wood texture deteriorated.
Furthermore, Comparative Examples 1 to 3 using an acrylic resin and a polycarbonate resin are resin components that do not use biogenic substances, and the degree of biomass is not improved.

  Although the present invention has been described in connection with the most practical and preferred embodiments at the present time, the present invention is not limited to the embodiments disclosed herein. The present invention can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and a wood resin molded article with such a change is also included in the technical scope of the present invention. Must be understood.

Claims (4)

A coating layer mainly composed of a polycarbonate resin containing a structural unit derived from a dihydroxy compound represented by the following formula (2) on the surface of a base material composed of a woody resin composition containing a thermoplastic resin and wood powder. Established
The content ratio of the structural unit derived from the dihydroxy compound represented by the following formula (2) of the polycarbonate resin is 30 mol% or more and 90 mol% or less,
A woody resin molded article obtained by adding an ultraviolet absorber in an amount of 0.2% by mass or less to 100% by mass of the total resin constituting the coating layer.

The polycarbonate resin is derived from a structural unit derived from a dihydroxy compound having a site represented by the formula ( 2 ) in a part of the structure, a structural unit derived from an aliphatic dihydroxy compound, or an alicyclic dihydroxy compound. It consists of a structural unit, The woody resin molding of Claim 1 characterized by the above-mentioned. 3. The woody resin molded article according to claim 1, wherein a glass transition temperature of the polycarbonate resin is 105 ° C. or more and 155 ° C. or less.   The ultraviolet absorber is added in a range of 0.0001% by mass to 0.2% by mass with respect to 100% by mass of the total resin constituting the coating layer. The woody resin molded article according to one item.