JP2017109344A - Method for manufacturing molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To widen a degree of freedom of selection of tree species which can be used as a woody material, and to reduce discomfort odor derived from the woody material.SOLUTION: In a method for manufacturing a molded product which includes a compound step of molding a plurality of pellets from a resin used as a binder and a woody material and a molding step of molding a molded product having a predetermined shape from the plurality of pellets, a heating step is provided between the compound step and the molding step, and the heating step includes heating the plurality of pellets at a temperature that enables a volatile component which is a source of burnt smell in the woody material to volatilize and is lower than the melting point of the resin.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for manufacturing a molded product including a resin as a binder and a wood material.

  This type of molded article contains cellulosic woody materials for environmental considerations, and is used for various applications such as vehicle exterior products and vehicle interior products. For example, in the technique disclosed in Patent Document 1, a plurality of cylindrical pellets are formed by heating and kneading wood powder as a wood material and a thermoplastic resin as a binder. Next, each pellet is heated and dried, and a molded product having a predetermined shape is formed using the plurality of dried pellets as a molding material. Moreover, in the technique disclosed in Patent Document 2, a good odor derived from the scented component (scent received by everyone) can be imparted to the molded product by introducing a scented component such as hinokitiol at the time of molding.

Japanese Patent Application Laid-Open No. 11-100140 JP 2011-6628 A

  By the way, in this type of molded product, an odor derived from the wood material may be generated, and an unpleasant odor (burnt odor) generated by heating the wood material has been regarded as a problem. That is, at the time of molding, the wood component is thermally decomposed, and the reaction product volatilizes at the use environment temperature (normal temperature to 100 ° C.) of the molded product, and this volatile component is perceived as a burning odor. The unpleasant odor derived from this wood material is derived from organic substances such as pyrolysis products of lignin (especially 4-vinyl-2-methoxyphenol) and pyrolysis products of hemicellulose (especially furfural). Volatile components (hereinafter also referred to as wood pyrolysis volatile components) are generated, and these odorous volatile components are not sufficiently removed by simply drying the pellet (heating at 100 ° C.). It was a thing. Although woody materials can be obtained from the tree species with the least volatile components, the degree of freedom in tree species selection is narrowed. Moreover, even if a scented component was used as in Patent Document 2, it was disturbed by an unpleasant odor and its effect was not fully exhibited. The present invention was devised in view of the above points, and the problem to be solved by the present invention is to increase the degree of freedom of selection of tree species that can be used as a wood material, while reducing the unpleasant odor derived from the wood material. It is to reduce.

  As means for solving the above-described problems, the method for manufacturing a molded product according to the first invention includes a compounding step of molding a plurality of pellets from a resin as a binder and a wood material, and a molded product having a predetermined shape from the plurality of pellets. A molding step of molding. In this type of molded article, it is desirable that the unpleasant odor derived from the wood material can be further reduced while the degree of freedom of selection of the tree species that can be used as the wood material is further expanded.

  Therefore, in the present invention, a heating step is provided between the compounding step and the molding step, and in this heating step, a plurality of pellets are at a temperature at which a volatile component that causes burnt odor in the woody material can volatilize and It was decided to heat at a temperature below the melting point of the resin. In the present invention, in the heating step, by heating a plurality of pellets at a temperature at which a volatile component that causes a burning odor can volatilize (for example, higher than 100 ° C.), the cause of an unpleasant odor derived from the woody material The volatile component can be suitably removed. At this time, by setting the upper limit of the heating temperature below the melting temperature of the resin, it is possible to heat while maintaining the shape of each pellet as much as possible.

  The method for producing a molded product according to the second invention is the method for producing a molded product according to the first invention, wherein the molded product is molded from a plurality of pellets and a scented component in the molding step. In the present invention, a good odor can be added to the molded product with reduced unpleasant odor by the scented component.

  The method for producing a molded product according to the third invention is the method for producing a molded product according to the first invention or the second invention, wherein in the compounding step, at least one of the group consisting of rice pine, rice candy, NZ pine, cherry blossom, rubber and cocoon. Use woody material obtained from a kind of tree species. In the present invention, by obtaining a wood material from a specific tree species, it is possible to preferably avoid excessive generation of a smell (such as an unpleasant smell) derived from the wood material in the molded article.

  According to the first invention of the present invention, the unpleasant odor derived from the wood material can be further reduced while further expanding the degree of freedom of selection of the tree species that can be used as the wood material. Furthermore, according to the first invention, it can be expected to simultaneously improve the VOC performance and fogging performance of the molded product. According to the second invention, a good odor can be suitably added to the molded article instead of the unpleasant odor derived from the wood material. And according to 3rd invention, it can avoid suitably that the smell derived from a wooden material arises excessively with respect to a molded article.

It is a figure which shows the manufacturing process of a molded article. It is the schematic of the pellet shaping | molding apparatus used for a compound process. It is the schematic of the shaping | molding apparatus used for a shaping | molding process.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to FIGS. The molded product of this example contains a cellulosic woody material in consideration of the environment, and can be used for various applications such as vehicle exterior products and vehicle interior products. In this type of configuration, it is desirable to be able to produce molded articles while reducing unpleasant odors (burnt odors) derived from wood materials as much as possible while using wood materials obtained from a wide variety of tree species. Therefore, in this embodiment, referring to FIG. 1, the compounding process, the heating process, and the molding process, which will be described later, are performed in this order, and the degree of freedom of selection of tree species that can be used as the woody material is further expanded, and derived from the woody material. An unpleasant odor was reduced. Hereinafter, each process is explained in full detail.

[Wood material]
Here, the woody material is a cellulosic material obtained from various tree species, and can be used in the compounding step described later in the form of powder or small pieces. In the present embodiment, an unpleasant odor can be suitably removed by a heating process described later, so that a woody material can be obtained from a wide variety of tree species (such as a tree species having a weak odor, a tree species having a strong odor, a tree species that can be used as a fragrance). For example, examples of the tree species having a weak odor include the pine family Tsuga such as rice husk (Tsuga Heterophylla), the pine family Togasawara such as rice pine, and the beech konara such as moth. In addition, as a pine family Tsuga group, a Tsuga (toga) and a rice moth can also be illustrated. The tree species with strong scents include pine pine such as New Zealand pine (NZ pine: Scientific name Pinus radiatea), cedars such as cedar, cedars such as cedar, euphorbiaceae such as rubber (para rubber tree), and rosaceae apples such as apples. Can be illustrated. Examples of tree species that can be used as a fragrance include the Rosaceae cherry family such as cherry blossoms and Yoshino cherry trees, and the Hinoki family cypress family such as camellia. Among them, it is preferable to use a woody material obtained from at least one kind of tree from the group consisting of rice pine, rice bran, NZ pine, cherry blossom, rubber (para rubber tree), and cocoon. The odor intensity is relatively low and is easy for everyone to receive. Furthermore, rice bran and rice pine are particularly preferable because they are readily available and contribute to the reduction of manufacturing costs.

[resin]
The resin that serves as the binder is a component that binds adjacent wooden materials, and various thermoplastic resins can be used. Examples of this type of thermoplastic resin include polyolefin resins such as polypropylene and polyethylene, polycarbonate resins, polyethylene terephthalate, polybutylene terephthalate, poly (ethylene-2,6-naphthalate), polyester resins such as nylon (polyamide), and propylene-ethylene copolymer. Polymers, polystyrene resins, copolymers of aromatic vinyl monomers and (meth) acrylic acid alkyl esters having lower alkyl groups, terephthalic acid-ethylene glycol-cyclohexanedimethanol copolymers, polymethyl methacrylate, etc. A (meth) acrylic resin can be illustrated. In addition, a thermoplastic resin can be used independently and can also be used in mixture of 2 or more types.

[Compound process]
In the compounding process, a plurality of pellets are formed from a resin and a wood material as a binder using the pellet forming apparatus PMM of FIG. Here, the shape and dimensions of each pellet are not particularly limited as long as it can be used as a molding material of a molded product. Examples of typical pellet shapes include columnar shapes such as a substantially cylindrical shape and a prismatic shape, and a granular shape such as a substantially spherical shape. In this embodiment, a substantially cylindrical pellet shape can be used. Further, the content of the woody material in the pellet is not particularly limited as long as it can be formed into a pellet by being bound with a resin as a binder. A typical wood material / resin content ratio (weight ratio) is in the range of 2:98 to 80:20, and preferably in the range of 10:90 to 60:40. Here, if the content ratio of the wooden material is less than 2, the meaning of using the wooden material for the molded article is almost lost. On the other hand, when the content ratio of the woody material is larger than 98, the binding force of the resin is extremely reduced, and pelletization becomes difficult. In addition to the resin and the wood material, various additives (a flame retardant, a pigment, a filler, etc.) can be added to each pellet.

  The pellet molding apparatus PMM is an apparatus for molding a pellet PT containing a resin RN serving as a binder and a wood material WD with reference to FIG. The pellet forming apparatus PMM of the present embodiment includes a base part 3p that supports the first charging part 2p and the second charging part 4p, a kneading part 6p, a cooling part 8p, a cutting part 10p, and a collecting part 12p. Prepare in order. Then, the resin RN is charged from the first charging part 2p and the wood material WD is charged from the second charging part 4p, and the resin RN and the wooden material WD are fed into the kneading part 6p. Next, in the kneading unit 6p, the resin RN is melted by heating and kneaded with the wood material WD to obtain a pellet molding material (reference numeral omitted), and then this pellet molding material is sent from the nozzle of the kneading unit 6p to the cooling unit 8p. put out. This pellet molding material is continuously sent out from the nozzle of the kneading part 6p and cooled by the cooling part 8p, for example, to become an elongated cylindrical base material (reference numeral omitted) following the shape of the nozzle opening. It is sent to the cutting unit 10p. Then, the cylindrical base material is sequentially cut by the cutting unit 10p to form a short cylindrical pellet PT, and the plurality of pellets PT are collected by the collection unit 12p.

[Heating process]
In the heating step, each pellet is heated at a temperature at which a volatile component that is a source of a burning odor in the wood material can be volatilized and less than the melting point of the resin. By providing this heating step between the compounding step and the molding step, the volatile component (woody pyrolysis volatile component) that causes the burnt odor can be volatilized from each pellet and sufficiently removed. That is, since each pellet is subdivided and has a large surface area as compared with the molded product, it can be quickly heated and the internal volatile components can be discharged to the outside. Here, the heating step can be performed using various heating devices (not shown) having a ventilation function. And in a heating process, it can heat in the state (state which left still) which laid several pellets in the heating apparatus, and can also heat, heating each pellet with a stirring mechanism.

  And the heating temperature in a heating process can be set to the temperature (typically higher than 100 degreeC) which can volatilize the volatile component used as the origin of a burning odor. In particular, from the viewpoint of removing wood pyrolysis volatile components that cause a burning odor, the heating temperature is preferably set to 120 ° C. or higher, and more preferably set to 140 ° C. or higher. Then, by setting the upper limit of the heating temperature below the melting temperature of the resin, it is possible to heat while maintaining the shape of each pellet as much as possible. The heating time in the heating step is not particularly limited as long as the volatile component (wood pyrolysis volatile component) that causes the burning odor can be suitably removed, but typically can be set to 30 minutes or more, and set to 1 hour or more. It is preferable to do. Here, the case where the volatile components in the woody material are suitably removed means that the overall judgment is judged as (◯) or ○ in the “odor test of molded article” described later.

[Molding process]
In the molding step, a molded product having a predetermined shape is molded from a plurality of pellets using a molding apparatus MM described later. Here, the shape of the molded product can be set to various shapes such as a board shape, a rod shape, and a rectangular shape, and is appropriately set according to the vehicle exterior product and the vehicle interior product that are assumed to be used. For example, in this embodiment, the board-shaped molded product MG shown in FIG. 3 can be molded assuming that it is used for a door trim as a vehicle interior product (in FIG. 3, for convenience, the molded product MG is hatched. And is shown in the figure).

  The molding apparatus MM is an apparatus that molds a molded product MG having a predetermined shape from a plurality of pellets PT with reference to FIG. 3, and includes an injection part XM, a mold YM that molds the molded product MG, and a mold clamping unit. ZM is provided in this order. Here, the injection part XM is a part where the pellet PT is melted to form a molding material, and a cylindrical screw 4x rotated around an axis by a motor 2x, and a cylindrical cylinder 6x in which the screw 4x is inserted. And a hopper 8x communicating with the cylinder 6x. The end of the cylinder 6x on the mold side is tightened in a conical shape, and an injection port 14x communicating with a mold YM, which will be described later, is provided at the tip, and a backflow prevention valve is provided on the injection port 14x side of the cylinder 6x. 12x is fitted. Further, a heater 10x is disposed on the outer peripheral surface of the cylinder 6x, and the pellet PT in the cylinder 6x can be heated and melted by the heater 10x. The mold YM includes a fixed mold 2y, a movable mold 4y, a cavity 6y, and a tie bar 8y. The cavity 6y is a molding space that follows the outer shape of the molded product MG, and is formed between the fixed mold 2y and the movable mold 4y in a closed state. The fixed mold 2y and the movable mold 4y are disposed so as to be relatively movable in the separating direction along the rod-shaped tie bars 8y disposed around them. The fixed mold 2y is provided with a sprue 3y (passage) for injecting the molding material sent from the injection part XM into the cavity 6y, and the movable mold 4y has an ejector rod 3z of the mold clamping part ZM described later. Are inserted so as to be relatively movable. The mold clamping part ZM is a part that brings the mold YM into a mold closed state. The ejector mechanism 2z for removing the molded product MG after formation, the ejector rod 3z provided in the ejector mechanism 2z, and the fixed mold 2y On the other hand, a cross head 4z for moving the movable die 4y back and forth is provided.

  Then, a plurality of pellets PT are put into the cylinder 6x from the hopper 8x. The plurality of pellets PT are melted in the cylinder 6x and kneaded by the screw 4x to form a molding material (not shown). The molding material is injected into the cavity 6y of the mold YM from the injection port 14x and has a predetermined shape. The molded product MG is formed. Then, after the mold YM is opened, the molded product MG molded into a predetermined shape can be taken out from the mold YM via the ejector rod 3z.

[Scented ingredients]
In the present embodiment, a scented component can be introduced into at least one of the above-described compounding step and molding step. Here, the scented component is a solid or liquid component that emits various good odors, and animal-based or plant-based natural and synthetic fragrances can be used. Among these, plant-based fragrances are preferably used as scented components because they are easily compatible with good odors derived from wooden materials. Examples of plant-based natural flavors include powders and small pieces of tree species that can be used as flavors, and essential oils such as hinoki oil and rose oil. Examples of plant-based synthetic fragrances include benzaldehyde (apricot scent), β-phenylethyl alcohol (rose scent), anisaldehyde (sweet scent), and coumarin. In addition, when using the powder and small piece of the tree species which can be used as a fragrance | flavor for a wooden material, this wooden material itself will act as a scented component.

  For example, in the present embodiment, referring to FIG. 3, in the molding step, the scented component is put into the hopper 8x together with each pellet PT, thereby molding a molded product MG from the plurality of pellets PT and the scented component. . In this way, by adding the scented component in the final process, wasteful volatilization and deterioration of the volatile component that is the source of the scent in the scented component are suitably suppressed, and a good odor derived from the same component is molded. Can be suitably applied. Here, the content of the scented component in the molded product is not particularly limited as long as an odor derived from the scented component can be imparted to the molded product. For example, the ratio of the weight of the wood material and resin combined to the weight of the flavoring component can be set in the range of 90:10 to 99: 1.

  As described above, in the present embodiment, in the heating step, it is possible to suitably remove volatile components that cause unpleasant odors derived from the wood material while maintaining the shape of the pellet as much as possible. For this reason, since the molded article of a present Example hardly has an unpleasant smell (burnt smell) derived from a wood material as mentioned above, it can be used suitably for various uses (especially vehicle interior goods). In the present embodiment, a good odor can be added to the molded product with reduced unpleasant odor by the scented component. In the present embodiment, the wood material is obtained from at least one kind of tree species selected from the group consisting of rice pine, rice bran, NZ pine, cherry blossom, rubber, and cocoon, whereby the smell of wood material derived from the molded product (unpleasant It is possible to favorably avoid excessive generation of no odor. For this reason, according to the present Example, the unpleasant smell derived from a wood material can be reduced more, expanding the freedom degree of selection of the tree species which can be used as a wood material. Furthermore, according to the present Example, in addition to the above-mentioned effect, it can be expected that the VOC performance (a reduction effect of volatile organic compounds) and the fogging performance (a glass fogging suppression effect) are also improved.

[Test example]
Hereinafter, although this embodiment is described based on a test example, the present invention is not limited to the test example. The following [Table 1] shows the resins and wood materials used in the molded articles of Examples 1 to 8. Table 2 below shows the resins and wood materials used in the molded articles of Example 9 and Reference Example 1. The following [Table 3] shows the results of the odor tests of Examples 1 to 9 and Reference Example 1, and the following [Table 4] shows the results of the odor tests of Comparative Examples 1 to 9.

[Example 1]
In Example 1, with reference to [Table 1], polypropylene (melting point: 165 ° C., manufactured by Sumitomo Chemical Co., Ltd., product number: AZ864) was used as a binder resin. Also, cedar (TABFB-WD1) powder was used as the wood material. In the compounding step, a plurality of cylindrical pellets (φ3 mm, length 3 mm) were formed from 90 parts by weight of resin and 11 parts by weight of woody material using the pellet forming apparatus of FIG. Next, using a heating device (model DRK633DB, manufactured by ADVANTEC), the plurality of pellets in a spread state were heated at 140 ° C. for 1 hour. In the molding step, a flat molded product (length 40 mm, width 60 mm, thickness 1.5 mm, weight 3.6 g) was formed from a plurality of pellets using the molding apparatus of FIG. This flat molded product can be used for, for example, a door trim which is a vehicle interior product.

[Examples 2 to 8]
In Examples 2 to 8, molded articles were produced under the same conditions and procedures as in Example 1 except that wood materials having different tree species were used. That is, referring to [Table 1], in Example 2, rice pine powder was used as the wood material. In Example 3, rice bran powder was used as the wood material. In Example 4, NZ pine powder was used as the wood material. In Example 5, cherry powder was used as the wood material. In Example 6, rubber powder was used as the woody material. In Example 7, oak powder was used as the wood material. In Example 8, apple powder was used as the wood material.

[Example 9, Reference Example 1]
In Example 9, a molded product was produced under the same conditions and procedure as Example 1 except that cherry powder was used as the wood material. In Reference Example 1, a molded product was produced under the same conditions and procedures as Example 9 except that the wood material was added in the molding process.

[Comparative Examples 1 to 9]
In Comparative Examples 1 to 8, molded products were produced under the same conditions and procedures as the corresponding examples except that the heating step was omitted. That is, each comparative example corresponds to an example having the same number. For example, comparative example 1 corresponds to example 1, and comparative example 8 corresponds to example 8. In Comparative Example 9, a molded article was produced under the same conditions and procedure as in Example 1 except that the plurality of pellets were heated at 100 ° C. (drying conditions) for 1 hour after the compounding step.

[Odor test of molded products]
The odor intensity and pleasantness / unpleasantness of the molded products of each Example, each Comparative Example, and Reference Example are described in accordance with the Architectural Institute of Japan Standard “AIJES-A007-2010 Indoor Odor Measurement Method Manual for Odors, p. 16, 2010. 9”. Measured based on (Architectural Institute of Japan). Here, the odor intensity is obtained by quantifying the “odor intensity”, and indicates that the odor intensity increases as the value increases. The degree of pleasure / discomfort is a numerical value of “degree of pleasure / discomfort”, and the greater the value, the stronger the degree of discomfort. And when judging the odor intensity and comfort / discomfort in a comprehensive manner, it is judged that it can be suitably used for vehicle interior parts, “○”, and when judged that it can be used for vehicle interior parts, “(○)” When it was determined that a problem would occur when used for a vehicle interior product, it was “X”, and when it was determined that it could not be used for a vehicle interior product, “XX” was assigned.

[Results and discussion]
Referring to [Table 4], it was found that the molded products of each comparative example can be used for vehicle interior products and some cannot. From this, it was found that omitting the heating step of the present example narrows the degree of freedom in selecting the tree species that can be used as the wood material. In addition, the molded product of Comparative Example 9 had a burning odor and was unusable for vehicle interior products. From this, it was found that an unpleasant odor cannot be removed only by heating a plurality of pellets at 100 ° C. (drying conditions) for 1 hour after the compounding step.

  And with reference to [Table 3], generation | occurrence | production of the burning odor was suppressed suitably for all the molded products of Examples 1-9, and it turned out that it can be used for vehicle interior goods. This is considered to be because the volatile component (woody pyrolysis volatile component) which is the source of the burning odor in each wooden material was sufficiently removed by performing the heating step. In particular, it was found that the molded articles of Examples 2 to 7 had a relatively low odor intensity (both had an odor intensity of 2 or less). For this reason, the use of a wood material obtained from at least one kind of tree from the group consisting of rice pine, rice candy, NZ pine, cherry blossom, rubber (para rubber tree) and cocoon has a relatively low odor intensity and is accepted by everyone. It was found that easy molded products can be obtained. Moreover, in Example 9 and Reference Example 1, with reference to [Table 3], it was found that the odor derived from the scented component can be suitably imparted to the molded product by the cherry as the scented component. In particular, it was easily inferred from Reference Example 1 that the odor derived from the scented component can be suitably imparted to the molded product by introducing the scented component in the molding step after the heating step. From these results, it was found that, in each example, by performing the heating step, an unpleasant odor derived from the wood material can be reduced while further increasing the degree of freedom of selection of the tree species that can be used as the wood material. Furthermore, according to the present Example, it was easily guessed that in addition to the above-described effects, VOC performance and fogging performance could be improved at the same time.

  The present embodiment is not limited to the above-described embodiments, and can take other various embodiments. In the present embodiment, the door trim is exemplified as the vehicle interior product, but the molded product of the present example can be used for various vehicle interior products and vehicle exterior products such as an instrument panel, a pillar garnish, and a console.

MG Molded product PT Pellet RN Resin WD Wood material PMM Pellet molding device 2p First input unit 4p Second input unit 6p Kneading unit 8p Cooling unit 10p Cutting unit 12p Collection unit MM Molding unit XM Injection unit 2x Motor 4x Screw 6x Cylinder 8x Hopper 10x heater 12x backflow prevention valve 14x injection port YM mold 2y fixed mold 3y sprue 4y movable mold 6y cavity 8y tie bar ZM clamping part 2z ejector mechanism 3z ejector rod 4z crosshead

Claims (3)

In a manufacturing method of a molded product comprising a compounding step of molding a plurality of pellets from a resin and a wood material as a binder, and a molding step of molding a molded product of a predetermined shape from the plurality of pellets,
A heating step is provided between the compounding step and the molding step, and in the heating step, the plurality of pellets are at a temperature at which a volatile component that causes a burning odor in the woody material can volatilize and the resin The manufacturing method of the molded article heated at the temperature below melting | fusing point of.   The method for producing a molded product according to claim 1, wherein in the molding step, the molded product is molded from the plurality of pellets and a scented component. The method for producing a molded article according to claim 1 or 2, wherein in the compounding step, the wood material obtained from at least one kind of tree selected from the group consisting of rice pine, rice candy, NZ pine, cherry blossom, rubber and cocoon is used. .