JP2007007869A - Manufacturing method of thermoplastic resin molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a thermoplastic resin molded product constituted by partially fusing a functional member to a thermoplastic resin foamed sheet shaped into a predetermined shape. <P>SOLUTION: The manufacturing method of the thermoplastic resin molded product includes a process (1) for supplying the thermoplastic resin foamed sheet to the space between a flat plate-shaped mold A, which has a molding surface having a recessed part for shaping the functional member formed thereto and evacuates at least the recessed part from its wall surface, and a flat plate-shaped mold B, a process (2) for closing the molds A and B, a process (3) for evacuating the recessed part from its wall surface in a state that the opening part of the recessed part formed to the molding surface of the mold A is closed by the thermoplastic resin foamed sheet in the process (2), a process (4) for supplying a molten thermoplastic resin to the recessed part through the resin passage provided to the mold A so as to communicate with the recessed part to integrally fuse the same to the thermoplastic resin foamed sheet and a process (5) for ejecting the thermoplastic resin molded product simultaneously with the stop of the supply of the molten thermoplastic resin or after the stop of the supply of the thermoplastic resin. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a thermoplastic resin molded article.

Foam molded articles obtained by molding a thermoplastic resin foam sheet are excellent in light weight, recyclability, heat insulation, and the like, and thus are used in various applications such as automobile members and building materials. A thermoplastic resin molded article in which a non-foamed functional member made of a thermoplastic resin such as a rib, boss, or hook is partially fused to a foam molded article is also known as an automobile interior part. As a method for producing a thermoplastic resin molded article in which such a non-foamed functional member is partially fused, a method including the following steps (1) to (4) is known (for example, Patent Document 1).
(1) A step of supplying a thermoplastic resin foam sheet preliminarily shaped into a predetermined shape between a pair of molds each having a functional member-shaped recess formed on at least one of them (2) closing the mold, Step of closing the opening of the recess with the thermoplastic resin foam sheet (3) Close the mold and close the opening of the recess with the thermoplastic resin foam sheet so that it passes through the recess. A step of supplying a molten thermoplastic resin to the recess through a resin passage provided in the resin passage, and fusing and integrating the thermoplastic resin and the thermoplastic resin foam sheet to form the thermoplastic resin molded article ( 4) Step of cooling the thermoplastic resin molded product formed in step (3) and removing it from the mold

JP 2001-121561 A

  Alternatively, when the shape of the thermoplastic resin product to be manufactured is complicated, for example, when the part where the functional member is fused is very elongated, the thermoplasticity in the molten state to form the functional member In order to fill the resin into the mold recess, it is necessary to supply the resin at a high temperature and a high pressure. However, when the molten thermoplastic resin is supplied to the recess at a high temperature and a high pressure by the above method, the deterioration of the resin is promoted and the appearance of the functional member may be poor.

  The present invention is a method for producing a thermoplastic resin molded article in which a functional member is partially fused to a thermoplastic resin foam sheet shaped into a predetermined shape, and the appearance of the functional member is good A method for producing a thermoplastic resin molded article is provided.

That is, the first aspect of the present invention is a method for producing a thermoplastic resin molded article in which a thermoplastic resin functional member is partially fused to a thermoplastic resin foam sheet shaped into a predetermined shape. The method includes the following steps in order.
(1) A flat plate-shaped mold A having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum-sucked from at least the wall surface of the recess, and a flat plate-shaped mold B (2) The step of supplying the thermoplastic resin foam sheet (2) The step of closing the mold A and the mold B (3) The step (2) of the recess formed on the molding surface of the mold A A step of vacuum suction from the wall surface of the recess while the opening is closed with the thermoplastic resin foam sheet (4) The molten thermoplastic resin is passed through the resin passage provided in the mold A so as to communicate with the recess. Step (5) of fusing and integrating the molten thermoplastic resin and the thermoplastic resin foam sheet (5) When the supply of the molten thermoplastic resin is stopped, the thermoplastic resin molded product is simultaneously or after being stopped. Extraction process

The second aspect of the present invention is a method for producing a thermoplastic resin molded article in which a thermoplastic resin functional member is partially fused to a thermoplastic resin foam sheet shaped into a predetermined shape. The method includes the following steps in order.
(1) A molding die A having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum-sucked at least from the wall surface of the recess, and a molding die paired with the molding die A (2) A step of supplying a thermoplastic resin foam sheet preliminarily shaped into a predetermined shape between B (2) a step of closing the mold A and a mold B (3) a step (2) of the mold A (4) Resin provided in the mold A so as to communicate with the recess, in a state where the opening of the recess formed on the molding surface is closed with the thermoplastic resin foam sheet and vacuum suction from the recess wall surface A step of supplying the molten thermoplastic resin to the recess through the passage and fusing and integrating the molten thermoplastic resin and the thermoplastic resin foam sheet (5) simultaneously with stopping the supply of the molten thermoplastic resin or The process of taking out the thermoplastic resin molded product after stopping

The third aspect of the present invention is a method for producing a thermoplastic resin molded article in which a thermoplastic resin functional member is partially fused to a thermoplastic resin foam sheet shaped into a predetermined shape. The method includes the following steps in order.
(1) Step of heating and softening a thermoplastic resin foam sheet (2) Molding having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum sucked from at least the wall surface of the recess A step of supplying the thermoplastic resin foam sheet obtained in the step (1) between the mold A and the mold B that forms a pair with the mold A (3) The mold A and the mold B are closed. In the state in which the opening of the recess formed on the molding surface of the mold A is closed with the thermoplastic resin foam sheet in the step (4) and the step (3) of shaping the thermoplastic resin foam sheet into a predetermined shape. (5) A molten thermoplastic resin is supplied to the concave portion through a resin passage provided in the mold A so as to communicate with the concave portion, and the molten thermoplastic resin and the thermoplastic resin are provided. Step of fusing and integrating the resin foam sheet (6) Molten heat After simultaneous or stopped when stopping the supply of the plastic resin, the step of taking out the thermoplastic resin molded article mold is opened

  According to the method for producing a thermoplastic resin molded article in which a functional member made of a thermoplastic resin is partially fused to the thermoplastic resin foam sheet of the present invention, the thermoplastic resin with good appearance of the functional member portion. A resin molded product can be obtained.

The present invention is a method for producing a thermoplastic resin molded article in which a thermoplastic resin functional member is partially fused to a thermoplastic resin foam sheet formed into a predetermined shape. The first aspect of the present invention is a method including the following steps.
(1) A flat plate-shaped mold A having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum-sucked from at least the wall surface of the recess, and a flat plate-shaped mold B (2) The step of supplying the thermoplastic resin foam sheet (2) The step of closing the mold A and the mold B (3) The step (2) of the recess formed on the molding surface of the mold A A step of vacuum suction from the wall surface of the recess while the opening is closed with the thermoplastic resin foam sheet (4) The molten thermoplastic resin is passed through the resin passage provided in the mold A so as to communicate with the recess. Step (5) of fusing and integrating the molten thermoplastic resin and the thermoplastic resin foam sheet (5) When the supply of the molten thermoplastic resin is stopped, the thermoplastic resin molded product is simultaneously or after being stopped. Extraction process

The second aspect of the present invention is a method including the following steps.
(1) A molding die A having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum-sucked at least from the wall surface of the recess, and a molding die paired with the molding die A (2) A step of supplying a thermoplastic resin foam sheet preliminarily shaped into a predetermined shape between B (2) a step of closing the mold A and a mold B (3) a step (2) of the mold A (4) Resin provided in the mold A so as to communicate with the recess, in a state where the opening of the recess formed on the molding surface is closed with the thermoplastic resin foam sheet and vacuum suction from the recess wall surface A step of supplying the molten thermoplastic resin to the recess through the passage and fusing and integrating the molten thermoplastic resin and the thermoplastic resin foam sheet (5) simultaneously with stopping the supply of the molten thermoplastic resin or The process of taking out the thermoplastic resin molded product after stopping

The third aspect of the present invention is a method including the following steps.
(1) Step of heating and softening a thermoplastic resin foam sheet (2) Molding having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum sucked from at least the wall surface of the recess A step of supplying the thermoplastic resin foam sheet obtained in the step (1) between the mold A and the mold B that forms a pair with the mold A (3) The mold A and the mold B are closed. In the state in which the opening of the recess formed on the molding surface of the mold A is closed with the thermoplastic resin foam sheet in the step (4) and the step (3) of shaping the thermoplastic resin foam sheet into a predetermined shape. (5) A molten thermoplastic resin is supplied to the concave portion through a resin passage provided in the mold A so as to communicate with the concave portion, and the molten thermoplastic resin and the thermoplastic resin are provided. Step of fusing and integrating the resin foam sheet (6) Molten heat After simultaneous or stopped when stopping the supply of the plastic resin, the step of taking out the thermoplastic resin molded article mold is opened

  In the present invention, a molding die A having a molding surface in which concave portions corresponding to the shape and number of functional members to be shaped are formed, and a molding die B that forms a pair with the molding die A are used. In the first aspect of the present invention, flat molds are used as the molds A and B. Molds A and B used in the second and third aspects of the present invention may be one male and the other female, both female or both plate-shaped. May be. Further, a recess for shaping the functional member may be formed on the molding surface of the mold B.

  In the mold A having a recess, a vacuum suction hole and a resin passage for supplying a molten thermoplastic resin to the recess are provided. The molten thermoplastic resin supplied to the recess is cooled to become a functional member. The functional member in the thermoplastic resin molded article obtained by the present invention is formed so as to protrude from the thermoplastic resin foam sheet, and the attachment position and the number of attachments of the functional member are not particularly limited. Specifically, it is a member having a function of reinforcing a thermoplastic resin molded product, or a member such as a boss, clip, or hook having a function of attaching the thermoplastic resin molded product to another member.

  The material of the mold is not particularly limited, but is usually made of metal from the viewpoint of dimensional stability and durability, and is preferably made of aluminum or stainless steel from the viewpoint of cost and light weight. Moreover, it is preferable that a shaping | molding die is a structure which can adjust temperature with a heater, a heat medium, etc. The molding die preferably has a molding surface of 30 to 80 ° C., more preferably 50 to 60 ° C. during the production of a thermoplastic resin molded product.

Hereafter, the manufacturing method of the thermoplastic resin molded product of this invention is demonstrated based on FIGS. 1-3. First, the first aspect of the present invention will be described in detail with reference to FIG.
FIG. 1- (1) shows a step (1), that is, a flat plate-shaped mold A having a molding surface formed with a recess for shaping a functional member and capable of being vacuum-sucked from at least the wall surface of the recess. And a step of supplying a thermoplastic resin foam sheet between the flat plate-shaped mold B.
Step (2) is a step of closing the mold A and the mold B. Since the thermoplastic resin foam sheet comes into contact with the molding surface of the mold by closing the mold, as shown in FIG. 1- (2), the opening of the concave portion provided on the molding surface of the mold is closed by the thermoplastic resin foam sheet. It becomes a state.

  Step (3) is a step of vacuum suction from the wall surface of the recess in a state where the opening of the recess formed on the molding surface of the mold A in step (2) is closed with the thermoplastic resin foam sheet. The degree of vacuum in the recess in the step (3) is preferably −0.05 to 0.1 MPa. The size of the vacuum suction hole provided in the recess may be such that the molten thermoplastic resin is not clogged in the vacuum suction hole when the molten thermoplastic resin is supplied to the recess, and the hole diameter is 0.1 to 0.5 mm. Preferably there is. FIG. 1- (3) shows a state in which the inside of the recess is depressurized by vacuum suction while the thermoplastic resin foam sheet is in close contact with the mold. In step (3) and step (4), which will be described later, in order to improve the adhesion between the opening of the recess and the foamed sheet, vacuum suction is performed from other than the recess wall surface of the mold A provided with the recess, or molding is performed. Compressed air may be supplied from the mold B.

In the step (4), a molten thermoplastic resin is supplied to the concave portion through a resin passage provided in the mold A so as to communicate with the concave portion, and the molten thermoplastic resin and the thermoplastic resin foam sheet are provided. This is a process of fusing and integrating. FIG. 1- (4) shows a state in which a molten thermoplastic resin and the thermoplastic resin foam sheet are fused and integrated. When supplying the molten thermoplastic resin to the recesses in the step (4), vacuum suction may be performed from the wall surfaces of the recesses as in the step (3). Step (5) is a step of taking out the thermoplastic resin molded product by opening the mold simultaneously with or after stopping the supply of the molten thermoplastic resin. FIG. 1- (5) shows a state where the mold is opened.

Next, a second embodiment of the present invention will be described with reference to FIG. Step (1) in the second aspect is a step of supplying a thermoplastic resin foam sheet that has been previously shaped into a predetermined shape. The mold A and the mold B to be used have the shape of the shaped foam sheet supplied between the molds A and B when the cavity shape formed by both mold surfaces when these molds are closed The mold has the same shape.
Steps (2) to (5) of the second aspect are the same as steps (2) to (5) of the first aspect, respectively.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3- (1) shows the step (1), that is, the step of heating and softening the thermoplastic resin foam sheet. The heating method is not particularly limited, and it can be heated with a heater or hot air.
Step (2) has a molding surface formed with a concave portion for shaping the functional member, and at least a molding die A that can be vacuum-sucked from the wall surface of the concave portion, and the molding die A This is a step of supplying the thermoplastic resin foam sheet obtained in the step (1) between the forming mold B.

  Step (3) is a step of closing the molding die A and the molding die B and shaping the thermoplastic resin foam sheet into a predetermined shape. Examples of the method for shaping the thermoplastic resin foam sheet include vacuum forming, pressure forming, vacuum pressure forming, and press forming. Since complex shapes can be easily formed, vacuum forming, pressure forming, and vacuum / pressure forming are particularly preferably applied. When the thermoplastic resin foam sheet is shaped by these methods, a mold capable of vacuum suction or supply of compressed air from the molding surface is used for at least one of the molds A and B. Specifically, the mold B can be vacuum-sucked, both molds A and B can be vacuum-sucked, the mold A can be supplied with compressed air, the mold B can be vacuum-sucked, and the mold A can be compressed air. Can be supplied. Examples of the mold capable of vacuum suction or supply of compressed air include a mold in which at least a part of the molding surface of the molding die is made of a sintered alloy, a mold in which holes are provided in at least a part of the molding surface, and the like. It is done. The number and position of holes provided in the mold and the hole diameter are not particularly limited.

When forming a thermoplastic resin foam sheet by vacuum forming, vacuum suction is started from the molding surface at the same time as the mold is closed or after the mold is closed, and the thermoplastic resin foam sheet is brought into close contact with the molding surface. Shape to a predetermined shape. Vacuum suction may be performed only from the mold B or from both molds. When vacuum suction is performed from both molds, the vacuum suction may be started simultaneously, or the vacuum suction may be started first from either one. When vacuum suction is performed from both molds, the molds may be opened while maintaining the state where the molding surfaces of the molds and the thermoplastic resin foam sheet are in close contact with each other. By this method, a thermoplastic resin molded product having a high expansion ratio can be obtained. The mold opening may be performed after supplying the molten thermoplastic resin to the recess or while supplying the molten thermoplastic resin. The degree of vacuum suction is not particularly limited, but vacuum suction is preferably performed so that the degree of vacuum between the mold and the foamed sheet is −0.05 to 0.1 MPa. The degree of vacuum is the pressure between the mold and the foam sheet with respect to atmospheric pressure. That is, “the degree of vacuum is −0.05 MPa” indicates that the pressure between the mold and the foamed sheet with respect to atmospheric pressure is 0.95 MPa. The degree of vacuum of the pressure between the mold and the foamed sheet with respect to atmospheric pressure is measured in a vacuum suction passage in the mold.

When the thermoplastic resin foam sheet is shaped into a predetermined shape by pressure forming, supply compressed air so that the degree of pressurization between the mold A and the thermoplastic resin foam sheet is about 2 to 5 MPa. Is preferred. The degree of pressurization between the mold A and the thermoplastic resin foam sheet is a pressure measured in the compressed air supply passage in the mold.
In the step (3), since the thermoplastic resin foam sheet is shaped in contact with the mold molding surface by closing the mold, as shown in FIG. 3- (3), the opening of the recess provided on the molding die molding surface. The part is closed by the thermoplastic resin foam sheet.

The step (4) of the third aspect includes the step (3) of the first aspect, the step (5) of the third aspect includes the step (4) of the first aspect and the third aspect. Step (6) is the same as step (5) of the first aspect. The vacuum suction and the supply of compressed air in the steps (4) to (5) of the third aspect may be performed continuously from the step (3), or may be performed again after stopping once.

  In the present invention, the molten thermoplastic resin supplied to the concave portion to form the functional member includes an olefin homopolymer having 2 to 6 carbon atoms such as ethylene, propylene, butene, pentene, hexene, Olefin resins such as olefin copolymers obtained by copolymerizing two or more types of monomers selected from olefins having a number of 2 to 10, ethylene-vinyl ester copolymers, ethylene- (meth) acrylic acid copolymer Examples thereof include a copolymer, an ethylene- (meth) acrylic acid ester copolymer, an ester resin, an amide resin, a styrene resin, an acrylic resin, an acrylonitrile resin, and an ionomer resin. These resins may be used alone or in combination with a plurality of resins. Olefin resins are preferably used from the viewpoints of moldability, oil resistance, cost, and the like, and propylene resins are particularly preferably used from the viewpoint of rigidity and heat resistance of the resulting functional member. When a polypropylene resin is used, a resin having MI = 50 to 100 g / 10 min is preferably used from the viewpoint of strength and ease of flow.

  The molten thermoplastic resin may contain an additive. Examples of the additive include a filler (filler), an antioxidant, a light stabilizer, an ultraviolet absorber, a plasticizer, an antistatic agent, a colorant, a release agent, a fluidity-imparting agent, a lubricant, and a foaming agent. Specific examples of the filler include inorganic fibers such as glass fibers and carbon fibers, inorganic particles such as talc, clay, silica, titanium oxide, calcium carbonate, and magnesium sulfate. Among these, it is preferable to mix about 5 to 30 wt% of talc or glass fiber from the viewpoint of improving the strength of the functional member or reducing the shrinkage rate during molding.

  As resin which comprises the thermoplastic resin foam sheet used by this invention, the same resin as resin which comprises the above-mentioned molten thermoplastic resin can be used. Olefin resins are preferably used from the viewpoints of moldability, oil resistance, cost, etc., and propylene resins are particularly preferably used from the viewpoint of rigidity and heat resistance of the obtained molded product.

  Examples of the propylene resin include a propylene homopolymer and a propylene copolymer containing 50 mol% or more of a propylene-derived structural unit. The copolymer may be any of a block copolymer, a random copolymer, and a graft copolymer. As an example of the propylene copolymer preferably used, a copolymer of ethylene or an α-olefin having 4 to 10 carbon atoms and propylene can be given. Examples of the α-olefin having 4 to 10 carbon atoms include 1-butene, 4-methylpentene-1, 1-hexene and 1-octene. The content of structural units derived from monomers other than propylene in the propylene-based copolymer is preferably 15 mol% or less for ethylene and 30 mol% or less for α-olefins having 4 to 10 carbon atoms. One type of propylene resin may be used, or two or more types may be mixed and used.

By using 50% by weight or more of the thermoplastic resin constituting the foam layer of a long-chain branched propylene resin or a high molecular weight propylene resin having a weight average molecular weight of 1 × 10 ⁵ or more, a propylene resin foam having fine bubbles is used. A sheet can be obtained. Further, among such propylene resins, non-crosslinked propylene resins are preferably used because gels are unlikely to occur during sheet recycling.

Here, the long-chain branched propylene-based resin refers to a propylene-based resin having a degree of branching index [A] satisfying 0.20 ≦ [A] ≦ 0.98.
An example of a long-chain branched propylene-based resin satisfying the branching index [A] of 0.20 ≦ [A] ≦ 0.98 is propylene PF-814 manufactured by Basel.

The degree of branching index indicates the degree of long-chain branching in a polymer and is a numerical value defined in the following formula.
Branch index [A] = [η] _Br / [η] _Lin
Here, [η] _Br is the intrinsic viscosity of the propylene resin having a long chain branch, and [η] _Lin is a straight chain having the same monomer unit and the same weight average molecular weight as the propylene resin having the long chain branch. It is an intrinsic viscosity of a chain propylene resin.
Intrinsic viscosity, also called intrinsic viscosity, is a measure of the ability of a polymer to enhance solution viscosity. Intrinsic viscosity depends in particular on the molecular weight of the polymer molecules and the degree of branching. Therefore, by comparing the intrinsic viscosity of a polymer having long chain branches with the intrinsic viscosity of a linear polymer having the same weight average molecular weight as that of the polymer having long chain branches, the degree of branching of the polymer having long chain branches can be determined. It can be a scale. The method for measuring the intrinsic viscosity of a propylene-based resin is described by Elliott et al. [J. Appl. Polym. Sci. , 14, 2947-2963 (1970)], for example, a propylene resin is dissolved in tetralin or orthodichlorobenzene, and the intrinsic viscosity at 135 ° C. Can be measured.
The weight average molecular weight (Mw) of the propylene-based resin can be measured by various commonly used methods. L. The method disclosed by McConnel in the American Laboratory, May, 63-75 (1978), that is, a low-angle laser light scattering intensity measurement method is particularly preferably used.
As an example of a method for polymerizing a high molecular weight propylene resin having a weight average molecular weight of 1 × 10 ⁵ or more, as described in JP-A No. 11-228629, a high molecular weight component is first polymerized, followed by low molecular weight. Examples thereof include a method of polymerizing components.

Among long-chain branched propylene resins or high-molecular-weight propylene resins, propylene resins having a uniaxial melt-extension viscosity ratio η ₅ / η _0.1 measured under the following conditions at around melting point + 30 ° C. are preferably 5 or more, more preferably 10 or more resins. The uniaxial melt extensional viscosity ratio is a value measured using an apparatus such as a uniaxial extensional viscosity measurement apparatus (for example, a uniaxial extensional viscosity measurement apparatus manufactured by Rheometrics, Inc.) at an elongation strain rate of 1 sec ⁻¹ . the uniaxial melt elongation viscosity after 0.1 seconds from the strain initiation and eta _0.1, the uniaxial melt elongation viscosity after 5 seconds and eta _5. By using a propylene-based resin having such uniaxial extensional viscosity characteristics, a foam sheet having finer bubbles can be produced.

  The foaming agent used to form the foamed sheet may be either a so-called chemical foaming agent or a physical foaming agent, or may be used in combination. Examples of the chemical foaming agent include a thermal decomposition type foaming agent that decomposes to generate nitrogen gas (azodicarbonamide, azobisisobutyronitrile, dinitrosopentamethylenetetramine, p-toluenesulfonylhydrazide, p, p'- Oxy-bis (benzenesulfonyl hydrazide) and the like, and pyrolytic inorganic foaming agents that decompose to generate carbon dioxide (sodium hydrogen carbonate, ammonium carbonate, ammonium bicarbonate, etc.) . Specific examples of the physical foaming agent include propane, butane, water, carbon dioxide gas, and the like. When the thermoplastic resin foam sheet is heated in the step (1), water, carbon dioxide, or the like is preferably used because deformation due to secondary foaming is less likely to occur, and ignition and flammability are low. The amount of the foaming agent used is appropriately selected according to the type of foaming agent and resin used so that a desired foaming ratio can be obtained. Usually, the foaming agent is used in an amount of 0.5 to 20 with respect to 100 weight of the thermoplastic resin. Parts by weight.

  The method for producing the thermoplastic resin foam sheet is not particularly limited, but a sheet obtained by extrusion molding using a flat die (T-die) or a circular die is preferable, and extrusion is performed while foaming the molten resin from the circular die. A method of stretching and cooling along a mandrel or the like is particularly preferably used. When the foamed sheet is produced by extrusion molding, the molten resin can be extruded from a die and solidified by cooling and then stretched. The foamed sheet may be a single layer or a multilayer, but from the viewpoint of preventing foam breakage during sheet production, a multilayered foam sheet having non-foamed layers in both outer layers is preferred. As the resin constituting the non-foamed layer, those described above as examples of the resin constituting the foamed layer can be used, but the same type of resin as that constituting the foamed layer is preferable. In the case of a propylene-based resin, the non-foamed layer is also preferably composed of a propylene-based resin. The thermoplastic resin foam sheet to be used is not particularly limited, and a foam sheet having an expansion ratio of 2 to 10 times and a thickness of about 1 to 10 mm is usually used.

The thermoplastic resin foam sheet used in the present invention may be a composite sheet obtained by laminating a single layer or multilayer foam sheet and another material. Such a composite sheet is obtained by laminating a foam sheet and another material by dry lamination, sand lamination, hot roll bonding, hot air bonding, or the like.
Examples of other materials to be laminated with the foamed sheet include materials that act as decoration, reinforcement, protection, and the like, and examples thereof include woven fabrics, nonwoven fabrics, sheets, films, foams, and nets. These materials include thermoplastic resins such as olefin resins, vinyl chloride resins, and styrene resins, rubbers such as polybutadiene and ethylene-propylene copolymers, thermoplastic elastomers, and cellulose fibers such as cotton, hemp, and bamboo. Can be mentioned. These materials may be provided with a concavo-convex pattern such as a texture, printed or dyed, and may have a single layer structure or a multilayer structure.
The foam sheet may contain an additive that can be blended with the above-described molten thermoplastic resin.

  The thermoplastic resin molded article obtained by the present invention can be used for packaging materials such as food containers, automobile interior parts, building materials, and home appliances. Examples of automobile interior parts include door trims, ceilings, and trunk sides. For example, if a thermoplastic resin molded product with ribs fused as a functional member is used as an automobile interior part, it will have excellent strength, and a thermoplastic resin molded product with bosses and hooks fused as functional members Can be easily connected to other automobile constituent materials.

EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to an Example at all.
[Example 1]

A thermoplastic resin molded product was manufactured by the method shown in FIG. 1 using a polypropylene foam sheet (product name: Sumiceller Foam PP sheet manufactured by Sumika Plustech Co., Ltd.) having an expansion ratio of 3 times and a thickness of 3 mm.
A mold A (3) having a recess (6) on the molding surface for forming a functional member in which ribs having a height of 10 mm, a length of 368 mm, and a width of 3 mm intersect each other in a cross shape can be shaped into a flat plate shape. A pair of molds made of the mold B (7) was used to mold a flat plate having ribs. The mold A is a mold having a vacuum suction hole with a hole diameter of 0.3 mm on the wall so as to communicate with the recess, and a resin passage (4) capable of supplying a molten thermoplastic resin. It was. Mold A (3) was used with its temperature adjusted to 60 ° C.
In a state where the thermoplastic resin foam sheet (1) is fixed to a clamp frame (2) of a vacuum forming machine (VAIM0301 manufactured by Sato Tekko Co., Ltd.) equipped with an extruder, the upper surface of the sheet is set to 180 ° C. by a near infrared heater. To soften. The foam sheet (1) softened by heating was supplied between the mold A (3) and the mold B (7) in a state of being fixed by the clamp frame (2).
Next, the mold A (3) and the mold B (7) were closed, and the thermoplastic resin foam sheet was shaped into a predetermined shape by press molding. With the opening of the concave portion of the mold A (3) closed with the thermoplastic resin foam sheet, vacuum suction was performed from the vacuum suction hole (5) on the concave wall surface, and the pressure in the concave portion was reduced to -0.6 MPa. .
Through a resin passage (4) in the mold A (3), a 220 ° C. molten thermoplastic resin (polypropylene manufactured by Sumitomo Chemical Co., Ltd., Nobrene AX568, MI = 65 g / min) is supplied at 10 g / sec into the mold recess for 5 seconds. Then, the concave portion was filled with a molten thermoplastic resin. After cooling the molded product by blowing air from a cooling fan, the mold was opened and the molded product was taken out. Unnecessary end portions were cut to obtain a flat plate (9) having ribs (8) as shown in FIG. The obtained flat plate having ribs did not discolor due to deterioration of the resin on the ribs and had a good appearance.

[Comparative Example 1]
In Example 1, a flat plate having ribs as in Example 1 except that the molten thermoplastic resin for forming the ribs was supplied to the recesses without reducing the recesses of the molding die (A). Manufactured.
Black portions due to deterioration of the resin were seen on the ribs.

Schematic of the first aspect of the method for producing a thermoplastic resin molded article of the present invention Schematic of the second embodiment of the method for producing a thermoplastic resin molded article of the present invention Schematic of the 3rd aspect of the manufacturing method of the thermoplastic resin molded product of this invention Plan view of flat plate with ribs

Explanation of symbols

1 Thermoplastic resin foam sheet 2 Clamp frame 3 Mold A
4 Resin passage 5 Vacuum suction hole 6 Recess 7 Mold D
8 Functional members (ribs)
9 Thermoplastic resin foam sheet 10 shaped in advance in a predetermined shape 10 Heat-softened thermoplastic resin foam sheet 11 Functional member (rib)
12 Thermoplastic resin molded product (flat plate)

Claims (3)

A method for producing a thermoplastic resin molded article, in which a thermoplastic resin functional member is partially fused to a thermoplastic resin foam sheet, the method comprising the following steps in order:
(1) A flat plate-shaped mold A having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum-sucked from at least the wall surface of the recess, and a flat plate-shaped mold B (2) The step of supplying the thermoplastic resin foam sheet (2) The step of closing the mold A and the mold B (3) The step (2) of the recess formed on the molding surface of the mold A A step of vacuum suction from the wall surface of the recess while the opening is closed with the thermoplastic resin foam sheet (4) The molten thermoplastic resin is passed through the resin passage provided in the mold A so as to communicate with the recess. Step (5) of fusing and integrating the molten thermoplastic resin and the thermoplastic resin foam sheet (5) When the supply of the molten thermoplastic resin is stopped, the thermoplastic resin molded product is simultaneously or after being stopped. Extraction process A method for producing a thermoplastic resin molded article, in which a thermoplastic resin functional member is partially fused to a thermoplastic resin foam sheet, the method comprising the following steps in order:
(1) A molding die A having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum-sucked at least from the wall surface of the recess, and a molding die paired with the molding die A (2) A step of supplying a thermoplastic resin foam sheet preliminarily shaped into a predetermined shape between B (2) a step of closing the mold A and a mold B (3) a step (2) of the mold A (4) Resin provided in the mold A so as to communicate with the recess, in a state where the opening of the recess formed on the molding surface is closed with the thermoplastic resin foam sheet and vacuum suction from the recess wall surface A step of supplying the molten thermoplastic resin to the recess through the passage and fusing and integrating the molten thermoplastic resin and the thermoplastic resin foam sheet (5) simultaneously with stopping the supply of the molten thermoplastic resin or The process of taking out the thermoplastic resin molded product after stopping A method for producing a thermoplastic resin molded article, in which a thermoplastic resin functional member is partially fused to a thermoplastic resin foam sheet, the method comprising the following steps in order:
(1) Step of heating and softening a thermoplastic resin foam sheet (2) Molding having a molding surface formed with a recess for shaping the functional member, and capable of being vacuum sucked from at least the wall surface of the recess A step of supplying the thermoplastic resin foam sheet obtained in the step (1) between the mold A and the mold B that forms a pair with the mold A (3) The mold A and the mold B are closed. In the state in which the opening of the recess formed on the molding surface of the mold A is closed with the thermoplastic resin foam sheet in the step (4) and the step (3) of shaping the thermoplastic resin foam sheet into a predetermined shape. (5) A molten thermoplastic resin is supplied to the concave portion through a resin passage provided in the mold A so as to communicate with the concave portion, and the molten thermoplastic resin and the thermoplastic resin are provided. Step of fusing and integrating the resin foam sheet (6) Molten heat After simultaneous or stopped when stopping the supply of the plastic resin, the step of taking out the thermoplastic resin molded article mold is opened

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