JP4239740B2 - Annealing method of plate-shaped thermoplastic resin molding - Google Patents

Description

  The present invention relates to a method for annealing a plate-shaped thermoplastic resin molded body. That is, for example, a plate-like thermoplastic resin molded body formed by an extrusion molding method, an injection molding method, or the like can be used to remove thermal strain and residual stress remaining after molding, correct deformation, or crystalline thermoplasticity. In the case of a molded body made of a resin, in the annealing performed for the purpose of increasing the strength by advancing the crystallization of the resin, deformation such as warpage and undulation that occurs in the annealing process, and local effects of the annealing effect The present invention relates to a method for annealing a plate-shaped thermoplastic resin molded body for preventing the occurrence of problems such as variations in physical properties due to various variations.

  A plate-shaped thermoplastic resin molded body formed by molding a thermoplastic resin such as polyolefin resin into a plate shape is a lightweight material that can be easily processed into any dimensions, and can be re-melted and recycled after use. As a substitute for wood and metal plates, it is used in a wide range of applications. For example, in the field of construction, instead of wood-based materials such as plywood that lead to destruction of the global environment due to deforestation because recycling is difficult, a molded body mainly composed of a thermoplastic resin that can be easily recycled is used. It has been proposed to be used as a building material. In particular, in order to approximate the texture such as the appearance and the feeling of touch and the workability such as sawing and nailing to a wood-based material, as shown in the following Patent Documents 1 and 2, a thermoplastic resin is also shown. There are also devised methods such as blending a wood-based filler such as wood powder or foaming it within a range that does not significantly impair its strength.

  However, a thermoplastic resin molded body molded by a known resin molding technique such as an extrusion molding method or an injection molding method has received a thermal history of heating for melting the resin and cooling for solidifying at the time of molding, Moreover, since the thermal history is performed at the very high speed of resin molding in order to maximize the production speed and optimize the production cost, thermal distortion and residual stress are likely to remain in the molded body after molding. . For this reason, there is a problem that the shape is not stable over time, or physical properties such as the strength of the material are not sufficiently exhibited. In particular, in a molded body using a crystalline thermoplastic resin, since the molten resin is cooled rapidly after molding, the resin is not sufficiently crystallized, and there is local variation in crystallinity. Therefore, there are problems that there are variations in physical properties such as strength of materials, and that the physical properties fluctuate due to crystallization over time.

  In order to solve the above problem, after molding the thermoplastic resin molded body, by heating to a temperature below its melting temperature (generally about 40 to 100 ° C.), A technique for removing the residual stress is generally called annealing. This method is extremely effective for molded products for applications where the accuracy of shape and dimensions is not very strict, and for molded products with nearly isotropic shapes, but is thinner than the length and width. In the case of a plate-shaped thermoplastic resin molded body, when the thermal strain and residual stress are released, the deformation due to it tends to concentrate in the thickness direction in which the plate-shaped molded body is easily deformed. The deformation is likely to occur. In particular, when the plate-like thermoplastic resin molded article contains an organic or inorganic filler or foams, the distribution and orientation state of the thermoplastic resin as the main component in the molded article is local. Due to the non-uniformity, deformation due to annealing is likely to occur non-uniformly, and thus the above-described problem is particularly likely to occur.

For this reason, especially in the use of building materials, due to deformation such as warpage and undulation of the plate-shaped thermoplastic resin molded body as the base material, warping, undulation, steps, etc. occur on the construction surface, and the design properties There is a problem in that workability is deteriorated due to difficulty in fitting and fixing with male and female berries at the end. Furthermore, in the case of a large-sized molded body used for building materials, it is difficult to heat and heat the entire molded body at a uniform rate, and due to the variation in the heating rate, the annealing effect is locally affected. There is also a problem that this may cause warpage, undulation, physical property variation, etc., especially when crystalline thermoplastic resin is used, due to local crystallinity variation. In addition, variations in physical properties are likely to occur.
JP 2001-353815 A JP 2002-120347 A

  The present invention has been made in order to solve the above-described problems in the prior art, and includes variations in physical properties due to deformations such as warping and undulation that occur in the annealing process, and local variations in the annealing effect. It is an object of the present invention to provide a method for annealing a plate-shaped thermoplastic resin molded body that prevents the occurrence of such problems.

  In order to solve the above-mentioned problem, first, in the invention of claim 1, when the plate-shaped thermoplastic resin molded body is annealed, the plate-shaped thermoplastic resin molded body is formed on the front and back surfaces and a pair of both side surfaces. A method for annealing a plate-shaped thermoplastic resin molded body is characterized in that a fixing plate for preventing deformation due to annealing of the sheet-shaped thermoplastic resin molded body is provided.

The invention according to claim 2 is characterized in that the fixing plate is made of a material having a thermal diffusivity at 20 ° C. of 2.0 × 10 ⁻⁵ [m ² / s] or more. The method for annealing the thermoplastic resin molded product was used.

  According to a third aspect of the present invention, there is provided the method for annealing a plate-shaped thermoplastic resin molded body according to the second aspect, wherein the fixing plate is made of aluminum alone or an alloy mainly composed of aluminum.

  In the invention of claim 4, a plurality of the plate-shaped thermoplastic resin molded bodies are stacked in the front and back direction, and the fixing plate installed on the front and back surfaces is a stack of the plate-shaped thermoplastic resin molded bodies. It sets to the front and back direction both ends of a body, It was set as the annealing method of the plate-shaped thermoplastic resin molding in any one of Claims 1-3 characterized by the above-mentioned.

  In the invention of claim 5, the plate-shaped thermoplastic resin molding is mainly composed of a crystalline thermoplastic resin, and the plate-shaped thermoplastic resin molding according to any one of claims 1-4. The body annealing method was used.

  In invention of Claim 6, the said plate-shaped thermoplastic resin molding contains an organic type and / or inorganic type filler, The plate-shaped heat in any one of Claims 1-5 characterized by the above-mentioned. An annealing method for the plastic resin molding was used.

  In the invention of claim 7, the plate-like thermoplastic resin molded product is foamed to a foaming ratio of 2 times or less, and the plate-like thermoplastic resin molding according to any one of claims 1 to 6, The body annealing method was used.

  The invention according to claim 8 is characterized in that the plate-like thermoplastic resin molded article has a decorative sheet mainly composed of a thermoplastic resin laminated on at least the surface thereof. An annealing method for the plate-like thermoplastic resin molded article described in the above was used.

  According to the annealing method of the plate-shaped thermoplastic resin molded body of the present invention, deformation due to the annealing of the plate-shaped thermoplastic resin molded body is prevented on the front and back surfaces of the plate-shaped thermoplastic resin molded body and the pair of both side surfaces. The plate-shaped thermoplastic resin molded body is fixed by a fixed plate that surrounds the four sides, so that deformation such as warping and undulation is suppressed. Is possible. Since the thermal strain and residual stress remaining inside the plate-shaped thermoplastic resin molded body can escape in the direction of the pair of both unfixed sides, the four sides are surrounded by a fixed plate. Can be removed sufficiently.

  In particular, by using a material having a high thermal diffusivity as the fixed plate, the temperature rise rate of the plate-shaped thermoplastic resin molded body is increased, and it becomes possible to perform rapid annealing and a local temperature difference is extremely high. Therefore, the local variation of the annealing effect is reduced, so that a plate-like thermoplastic resin molded article having uniform physical properties can be obtained.

  In addition, by stacking a plurality of plate-shaped thermoplastic resin molded products in the front and back direction, many plate-shaped thermoplastic resin molded products can be annealed at a time, which is excellent in work efficiency. In addition, according to the method of the present invention, when the plate-like thermoplastic resin molded body has a crystalline thermoplastic resin as a main component, the resin is uniformly crystallized over the entire molded body. And physical properties such as surface hardness are improved uniformly. Further, the method of the present invention is extremely effective even when an organic or inorganic filler is contained, foamed, or a decorative sheet is laminated on the surface.

  As an example of the annealing method for the plate-shaped thermoplastic resin molded article of the present invention, an example of an annealing method for a floor material based on a plate-like wood resin foam molded article will be described in detail below with reference to the drawings. However, the present invention is of course not limited to this.

  The woody resin foam molded article as the base material of the flooring material used here is, for example, a thermoplastic resin such as a polyolefin resin such as polypropylene, a polyester resin such as polyethylene terephthalate, a styrene resin such as polystyrene or ABS. Preferably, the main component is a crystalline thermoplastic resin. Typically, it is a polypropylene resin. In order to give the resin rigidity, dimensional stability, texture and workability similar to wood, organic fillers such as wood powder obtained by pulverizing wood, silica, talc, calcium carbonate, etc. In general, an inorganic filler or the like is blended in an amount of about 10 to 400 parts by weight per 100 parts by weight of the resin. The base material of the flooring material may be non-foamed, but it is often foamed within a range of a foaming ratio of 3 times or less that does not impair strength, for the purpose of weight reduction, imparting elasticity and heat insulation. . In many cases, the outer dimensions are long plate shapes having a thickness of about 2 to 20 mm, a width of about 50 to 300 mm, and a length of about 900 to 3600 mm. In addition, a fitting structure such as male / female fruit, mating or phase notch for connecting floor materials to each other is provided on the side face, particularly at least the side face parallel to the longitudinal direction. It is common.

  In general, a decorative sheet is laminated on the surface of a wooden resin foam molded article for the purpose of surface decoration for imparting design properties. In that case, the annealing treatment of the wood resin foam molded body in the flooring material may be performed before or after lamination of the decorative sheet, and is performed twice before and after lamination. Of course you can go. If it is carried out after the lamination of the decorative sheets, there is also an advantage that the adhesive used for the lamination of the decorative sheets can also be cured (aging). Hereinafter, the presence or absence or the front and back of the decorative sheet may be simply referred to as a wood resin foam molded body or a flooring material without particular distinction.

  In the annealing treatment of the wood resin foam molded product or floor material, as shown in FIGS. 1 and 2, an annealing stand is prepared, and the long plate-like wood resin foam molded product or floor material is placed therein. A general method is to install in a flat stack and heat for a predetermined time in an annealing room maintained at a constant temperature as a gantry. Accessories such as wheels and handles may be attached to the dedicated mount for convenience of transportation and the like.

  The physical properties required for this annealing mount are sufficient so that the weight and weight of the wooden resin foam molded article or flooring do not cause deformation or deflection of the mount. It must be rigid. This is because if the annealing is performed with the pedestal being deflected, the wooden resin foam molded article and the flooring material are affected by the deformation and the deflection and are deformed.

  In order to uniformly heat the woody resin foam molded article or flooring, it is desirable to use a material having a high thermal diffusivity for the gantry. The thermal diffusivity is defined as a value obtained by dividing the thermal conductivity of a substance by the density and specific heat. The larger this value, the easier the heat (temperature) is transferred in an unsteady state. If a frame made of a material with a low thermal diffusivity is used, heat and cold air are likely to stay in the frame, resulting in uneven heating of the wood resin foam or flooring material, and local effects on the annealing effect. Variations are likely to occur. In particular, when the main component of the wood resin foam molded article is a crystalline thermoplastic resin, the crystallinity varies. As a result, physical properties after construction as a flooring material, particularly surface scratch resistance, are likely to be greatly affected. In addition, a fitting structure such as male and female for connecting floor materials to each other is often provided on the side surface of the wood resin foam molded product or floor material, so this fitting performance becomes non-uniform. In the worst case, the fitting itself may be impossible.

  Further, in order to uniformly heat the wood resin foam molded product or the floor material, it is necessary to design the gantry shape in consideration of less heat retention.

  Examples of the material having the physical properties listed above include silver, copper, aluminum alone or an alloy containing these as a main component, reinforced plastic, and the like. As a result of comprehensive consideration of durability, including non-hardness, etc., it is desirable to use aluminum alone or alloyed with this as the main component. A grid or a combination of diagonal shapes is desirable.

  What is important in the present invention is that the wooden resin foam molded article or flooring is flattened on the annealing base and flattened, that is, as shown in FIG. It is to install the fixing plates 1 to 4 for preventing deformation of the wood resin foam molded body or floor material from the pair of both side surfaces and the front and back directions of the wood resin foam molded body or floor material 5. (Note. In the example shown in FIG. 3, the fixing plate 4 in the back direction of the wood resin foam molded article or flooring 5 also serves as the mounting surface of the annealing base. As in this example, the fixing plate 1 A part or all of ˜4 may also serve as a component of the annealing base. Thereby, in the heating by annealing, the wooden resin foam molded body or flooring 5 can suppress deformation such as warpage by the fixing plates 1 to 4 surrounding the four sides. In the case of a long floor material, it is preferable to select both side surfaces parallel to the longitudinal direction of the wooden resin foam molded article or floor material, that is, both width side surfaces, as the pair of both side surfaces. When warping or distortion occurs on both side surfaces, it becomes extremely difficult to connect and construct floor materials by fitting male and female in the width direction.

  The fixing plates 1 to 4 are firmly fixed to each other by screwing or the like so as to suppress deformation of the wood resin foam molded article or flooring 5 due to heating, or using air pressure or a spring, etc. It is good to impose the pressure of the direction which compresses a foaming molding or the flooring 5. In addition, about the front-and-back surface direction of the wood resin foam molded object or the flooring 5, you may utilize the dead weight of the stationary plate 3 mounted on the surface.

  The physical properties required for the material of the fixing plates 1 to 4 are substantially the same as those required for the material of the above-described annealing mount. That is, the material needs to have sufficient rigidity and thermal diffusivity.

  When a material that does not have sufficient rigidity is used, the force that the wood resin foam molded article or flooring 5 tends to deform due to annealing cannot be suppressed. Warpage may occur. In that case, it is necessary to forcibly suppress the force to deform the woody resin foam molded article or flooring 5 by increasing the thickness of the fixing plates 1 to 4 or overlapping a plurality of sheets.

As for the thermal diffusivity, it is desirable to use a material having a thermal diffusivity at 20 ° C. of 2.0 × 10 ⁻⁵ [m ² / s] or more. When a material having a thermal diffusivity of 2.0 × 10 ⁻⁵ [m ² / s] or less is used, not only an extra annealing time is required, but also the addition to the wood resin foam molded article or flooring 5 Heat transmission becomes uneven, and local variations are likely to occur in the annealing effect. In particular, when the main component of the wood resin foam molded article is a crystalline thermoplastic resin, the crystallinity varies. As a result, the physical properties after construction, particularly scratch resistance, and the fitting between adjacent floor materials become non-uniform.

  Examples of the material having the physical properties listed above include silver, copper, aluminum alone or an alloy containing these as a main component, reinforced plastics, and the like. When comprehensively considering durability including rust resistance, it is desirable to use aluminum alone or an alloy containing it as a main component.

  The annealing of wood resin foam moldings or flooring materials improves the strength of the molded product and at the same time increases the dimensional stability of the molded product by removing the distortion of the molded product caused by heat and mechanical stress. Things are the biggest purpose. Therefore, when the wooden resin foam molded article and the floor material are annealed, it is necessary to secure a clearance for the molded article in advance. In the example of the present invention, the width direction of the wood resin foam molded body and the floor material and the surface excluding the front surface direction and the back surface direction, that is, the end surface of the long floor material, which is a side surface perpendicular to the longitudinal direction ( (This surface is the cut surface of the molded product when the wood resin foam molded product is molded by the extrusion method in the longitudinal direction.) By doing so, the distortion of the molded product is removed. On the other hand, when a fixing plate is also installed on the end of the wood, the distortion of the molded product is not completely removed, and the effect is limited.

Specific examples of the present invention will be described below.
[Example 1]
MFR (melt flow rate) specified in JIS K 6760 is 30 parts by weight of homopolypropylene resin with 6 g / 10 min, 10 parts by weight of homopolypropylene resin modified with maleic acid, and wood is broken with a cutter mill, and this is pulverized with a ball mill. Then, 60 parts by weight of a wood filler having an average particle size of 100 μm made into a fine powder was mixed by a twin-screw extrusion kneader and pelletized to produce a wood resin composition of wood polyolefin resin.

  To 50 parts by weight of this wood resin composition, 46 parts by weight of homopolypropylene having an MFR (melt flow rate) of 0.5 g / 10 min and 4 parts by weight of a sodium bicarbonate citrate foaming agent were added, and this was uniaxially extruded. Using a SELKA process, the cross-sectional dimension is approximately 4mm x 300mm, and a male / female mating structure is provided on the side surface. The length is 2000mm and the expansion ratio is 1.4. A resin foam molding was produced.

Thirty sheets of the wooden resin foam molded product are placed horizontally, and an aluminum plate having a thermal diffusivity of 9.1 × 10 ⁻⁵ [m ² / s] at 20 ° C. from four directions surrounding the cross section is molded with the wooden resin foam. It was installed so as to surround the body, and a pressure of 330 Pa was applied from the surface direction by the weight of the aluminum plate. Further, from both sides, a pressure of 400 Pa was applied by a spring device to prevent the collapse of the load, and annealing was performed for 48 hours at a temperature of 80 ° C. as it was, and the wood resin foam molded body annealed according to Example 1 was obtained. Obtained.
[Example 1 ']
On the other hand, a colored polypropylene sheet with a thickness of 70 μm formed by blending pigments such as iron oxide and titanium oxide with random polypropylene is printed with a grain of urethane ink, and transparent homopolypropylene resin is 90 μm by extrusion lamination. After carrying out the simultaneous embossing treatment at the thickness of the sheet, a primer sheet was applied to the back surface of the sheet, and a surface protective coating was applied to the surface to prepare a decorative sheet, and the surface was subjected to corona treatment. The flooring using the wooden resin foam molded body was obtained by bonding to the surface of the wooden resin foam molded body using a lapping method.

This flooring is placed horizontally and stacked in 30 sheets, and an aluminum plate with a thermal diffusivity of 9.1 × 10 ⁻⁵ [m ² / s] at 20 ° C. from four directions surrounding the cross section is installed so as to surround the flooring. A pressure of 330 Pa was applied from the surface direction by the weight of the aluminum plate. In addition, from both sides, a pressure of 400 Pa was applied by a spring device to prevent load collapse, and annealing was performed for 48 hours at a temperature of 80 ° C. as it was to obtain an annealed flooring material according to Example 1 ′. .
[Example 2]
Example 2 was annealed in the same manner as in Example 1 except that a titanium plate having a thermal diffusivity at 20 ° C. of 0.6 × 10 ⁻⁵ [m ² / s] was used instead of the aluminum plate. A wood resin foam molding was obtained.
[Example 2 ']
Example 2 ′ was performed in the same manner as in Example 1 ′ except that a titanium plate having a thermal diffusivity at 20 ° C. of 0.6 × 10 ⁻⁵ [m ² / s] was used instead of the aluminum plate. An annealed flooring was obtained.
[Comparative Example 1]
A woody resin foam molded article annealed in Comparative Example 1 was obtained by using the same method as in Example 1 except that the aluminum plate was not installed from four directions surrounding the cross section during annealing.
[Comparative Example 1 ']
A flooring annealed in Comparative Example 1 ′ was obtained using the same method as in Example 1 ′ except that the aluminum plate was not installed from the four directions surrounding the cross section during annealing.
〔result〕
The results are shown below.

* 1 The variation in scratch resistance was determined by measuring the hardness of a plurality of arbitrary points on the surface of a single woody resin foam molded article by a method according to JIS K 6253.

  * 2 The results of the flooring materials of Example 1 ′, Example 2 ′ and Comparative Example 1 ′ are significantly different from the results of Examples 1, Example 2 and Comparative Example 1 of the wood resin foam molded bodies shown in Table 1. I omitted it for no reason.

  As can be seen from the above results, the degree of warping of the base material is suppressed in the case where the fixing plate is present (Example 1, Example 2) than in the case where there is no fixing plate (Comparative Example 1). I understand that Further, it can be seen that due to the warp and the like, the fitting state of the wood resin foam moldings is also affected. In addition, regarding the variation in scratch resistance, there is a tendency that the variation in Example 2 using a titanium plate having a low thermal diffusivity is large.

The front view of the mount for annealing used for this invention. The side view of the mount for annealing used for this invention. The front view explaining the annealing method of this invention.

Explanation of symbols

1-4 Fixed plate 5 Plate-shaped thermoplastic resin molding (woody resin foam molding or flooring)

Claims (8)

  When annealing a plate-shaped thermoplastic resin molded body, fixing is performed on the front and back surfaces of the plate-shaped thermoplastic resin molded body and a pair of both side surfaces to prevent deformation due to annealing of the plate-shaped thermoplastic resin molded body. A method for annealing a plate-like thermoplastic resin molded article, comprising installing a plate. ^2. The plate-like thermoplastic resin molded body according to claim 1, wherein the fixing plate is made of a material having a thermal diffusivity at 20 ° C. of 2.0 × 10 ⁻⁵ [m ² / s] or more. Annealing method.   The method for annealing a plate-shaped thermoplastic resin molded body according to claim 2, wherein the fixing plate is made of aluminum alone or an alloy mainly composed of aluminum.   A plurality of the plate-shaped thermoplastic resin molded bodies are stacked in the front and back direction, and the fixing plates installed on the front and back surfaces are both end portions in the front and back direction of the stacked body of the plate-shaped thermoplastic resin molded bodies. The method for annealing a plate-shaped thermoplastic resin molded body according to any one of claims 1 to 3, wherein the method is provided for mounting in a sheet.   The method for annealing a plate-shaped thermoplastic resin molded body according to any one of claims 1 to 4, wherein the plate-shaped thermoplastic resin molded body contains a crystalline thermoplastic resin as a main component.   The method for annealing a plate-shaped thermoplastic resin molded article according to any one of claims 1 to 5, wherein the plate-shaped thermoplastic resin molded article contains an organic and / or inorganic filler. .   The method for annealing a plate-shaped thermoplastic resin molded body according to any one of claims 1 to 6, wherein the plate-shaped thermoplastic resin molded body is foamed to a foaming ratio of 3 times or less.   The plate-like thermoplastic resin according to any one of claims 1 to 7, wherein a decorative sheet mainly composed of a thermoplastic resin is laminated on at least a surface of the plate-like thermoplastic resin molded body. An annealing method for a plastic resin molding.