JP6619165B2 - Process for producing sheet-like or plate-like extruded foam containing plant-derived components - Google Patents

Description

The present invention relates to a method for producing a sheet-like or plate-like extruded foam containing a plant- derived component .

  Foams mainly composed of foaming plastics such as polystyrene, polypropylene, polyethylene, polyester and the like are rich in heat insulating properties and buffer properties, and are used as heat insulating materials, buffer materials and packaging containers.

  When this foamed plastic is formed into a sheet or plate, for example, pre-expanded beads are kneaded into the foaming plastic, molded into a sheet or plate, and then heat treated to foam the announced beads. By this bead method, for example, polystyrene can be foamed to obtain a foamed polystyrene sheet having a thickness of about 0.5 mm.

  In recent years, awareness of the natural environment has increased, and environmental protection efforts have been screamed. As part of this effort, there is a need for “foams” using environmentally friendly materials (for example, plant-derived ingredients). For example, Patent Document 1 discloses an extruded foam mainly composed of government-made postcard paper as a foam that is gentler to the natural environment than a conventional foam (for example, foamed styrene). This extruded foam can be obtained by kneading government-made postcard waste paper as a main component, polypropylene as a resin component, and corn starch as an auxiliary agent, and then extruding them.

JP 2001-354895 A

  However, the extruded foam described in Patent Document 1 has a bowl-like (rod-like) body, and its shape tends to become unstable. Therefore, it may be used for filling the marginal space of the packing box, but there is a problem that it is difficult to obtain a sheet-like or plate-like extruded foam.

  In addition, in the process for producing the extruded foam described in Patent Document 1, it is necessary to pulverize the government-made postcard paper with a mixer cutter type pulverizer before kneading the government-made postcard paper and other components (polypropylene resin or corn starch). There is. However, in order to pulverize government-made postcard paper using a mixer-cutter type pulverizer, time and equipment required for this pulverization are separately required, so low production efficiency and high production cost are problems. Yes. In particular, the increase in power required for pulverization is not sufficient from the viewpoint of environmental protection. Further, the foam obtained in this way cannot be said to have sufficient surface cosmetics and compressive strength, and its improvement is required.

  Furthermore, the foamed plastic sheet using the conventional bead method has a problem that it is necessary to highly control the temperature of the manufacturing process.

In view of such circumstances, the present invention is intended to provide a sheet-like or plate-like extruded foam containing starch and / or vegetable cellulose.

The sheet-like or plate-like extruded foam containing the plant- derived component of the present invention is formed into a sheet-like or plate-like shape, and starch and / or vegetable cellulose as main components, a foaming plastic, and the plant cellulose And a modifier for the mixture containing the foaming plastic.

  In relation to the sheet-like or plate-like extruded foam, the foaming plastic is a mixture of a polypropylene resin and an ethylene resin and / or a styrene resin.

  In relation to the sheet-like or plate-like extruded foam, the ratio of the total weight of the ethylene resin and / or the styrene resin in the foaming plastic is 20% or more and 40% or less. And

  In relation to the sheet-like or plate-like extruded foam, the ratio of the total weight of the ethylene resin and / or the styrene resin to the whole foam is 5% or more and 15% or less. And

In connection with the sheet-like or plate-like extruded foam, prior SL starch and / or vegetable in the cellulose, paper pulp-based cellulose, characterized in that it is contained in 30 wt% or less.

  In connection with the sheet-like or plate-like extruded foam, the modifying agent is an acrylic modified body of polytetrafluorotoluene.

The sheet-like or plate-like extruded foam containing the plant- derived component of the present invention is molded into a sheet-like or plate-like shape, the foaming plastic as the main component, starch and / or vegetable cellulose, and the foaming plastic And a modifying agent for the mixture containing starch and / or vegetable cellulose.

  In relation to the sheet-like or plate-like extruded foam, the foaming plastic is a mixture of a polypropylene resin and an ethylene resin and / or a styrene resin.

  In connection with the sheet-like or plate-like extruded foam, the modifying agent is a polytetrafluorotoluene acrylic modified body.

  The method for producing an extruded foam includes a powder blend preparation step of preparing a powder blend from the mixture to which a foaming agent is added, when a mixture including vegetable cellulose and foaming plastic is defined as a mixture. And an extrusion foaming step of performing extrusion foaming on the powdery composition.

  In relation to the method for producing the extruded foam, the extrusion foaming step utilizes an extrusion kneader, and the extrusion die is provided with strand-like openings through which the extrudate passes in a row or a plurality of rows. The tip of the die has a foaming space forming portion constituting a sheet-like or plate-like outer shape.

  In relation to the method for producing the extruded foam, the extrusion foaming step utilizes an extrusion kneader, and the extruder die is provided with one or more slits through which the extrudate passes, and the tip of the die is provided. Has a foaming space forming portion constituting a sheet-like or plate-like outer shape.

  ADVANTAGE OF THE INVENTION According to this invention, the extrusion foam with the characteristic which is kind to a natural environment compared with the past can be provided.

It is a flowchart which shows the outline | summary of the manufacturing method of an extrusion foam. In the twin-screw extruder used in the production of the extruded foam, (A) a plan view showing the kneading part and the vicinity of the die in an enlarged manner, (B) a front view of the vicinity of the die viewed from the downstream side, (C) the twin-screw extrusion It is the front view which looked at the other die structure of the machine from the downstream. It is a photograph which shows the definition of the characteristic evaluation of an extrusion foam.

  <First embodiment>

Hereinafter, a first embodiment of the present invention will be described with reference to the accompanying drawings. In the first embodiment, a sheet-like or plate-like extruded foam (hereinafter referred to as an extruded foam) having starch and / or vegetable cellulose as a main component is established.

(Extruded foam)
The extruded foam includes a main component, a foaming plastic, a foaming agent, a modifier, and an additive.

(Main component)
The main component is a component friendly to the natural environment, and uses starch and / or vegetable cellulose. Examples of the starch and / or vegetable cellulose component include starch (for example, corn starch, tapioca starch, potato starch, glutinous rice starch, and wheat starch), paper pulp, and the like. In addition, it is preferable that this main component does not contain government-made postcard waste paper. In addition, as a definition of a main component, it means here that the weight ratio of starch and / or vegetable cellulose is larger than the plastic for foaming.

The content of starch and / or vegetable cellulose as the main component for the whole extruded foam is preferably 35% by weight or more, and more preferably 45% by weight or more. The upper limit of the content of vegetable cellulose as a main component for the entire extruded foam is not particularly limited as long as it is within a range where an extruded foam can be obtained in relation to the content of other components.

Moreover, the upper limit of the content of the main component ( starch and / or vegetable cellulose) with respect to the foaming plastic is not particularly limited as long as it is within a range where an extruded foam can be obtained. For example, it is preferably 350% by weight or less, and more preferably 300% by weight or less.

(Foaming plastic)
Examples of the foaming plastic include polypropylene, styrene resin (eg, polystyrene, high impact polystyrene, ABS, etc.), ethylene resin (eg, high density polyethylene, low density polyethylene, ethylene vinyl acetate copolymer resin, etc.), polyester, and the like. From the viewpoint of ease of production, polypropylene and polystyrene are mainly used.

  The content of the foaming plastic with respect to the entire extruded foam is preferably, for example, from 10% by weight to less than 50% by weight, and more preferably from 25% by weight to 45% by weight.

  The proportion of the total weight of the ethylene resin and / or styrene resin in the foaming plastic is preferably 20% or more and 40% or less. Moreover, it is preferable that the ratio of the total weight of ethylene-type resin and / or styrene-type resin is 5% or more and 15% or less with respect to the whole extrusion foam.

(Foaming agent)
As the foaming agent, known organic and inorganic foaming agents can be appropriately selected and used. However, in the case of an organic foaming agent, aspects such as explosion-proof management, ensuring product safety, and environmental protection, etc. Is not preferable. Therefore, it is preferable to use an inorganic foaming agent. Examples of the inorganic foaming agent include water, air, carbon dioxide, nitrogen, argon, helium, and the like, but it is preferable to use water because it can be used in an open system in the atmosphere.

  The content of the foaming agent with respect to the entire extruded foam is not particularly limited as long as it is within a range where an extruded foam can be obtained. For example, the content range is preferably 1% by weight to 8% by weight, and more preferably 3% by weight to 6% by weight.

(Additive)
Examples of the additive include a modifier, a nucleating agent, a coloring material, a deodorant, and an antibacterial agent.

Hereinafter, for convenience of explanation, a mixture of starch and / or vegetable cellulose as a main component, plastic for foaming, and an additive is referred to as a mixture.

(Modifier)
The modifier is for improving the melt tension of the mixture (in particular, starch and / or vegetable cellulose and foaming plastic) and improving the compatibility in the mixture. The modifier is an acrylic modified product of polytetrafluoroethylene. More specifically, the modifier is composed of polytetrafluoroethylene (A) and an alkyl (meth) acrylate polymer (B) having 5 to 30 carbon atoms. As a specific example, there is Metabrene A3000 manufactured by Mitsubishi Rayon Co., Ltd. The content of the modifier with respect to the entire extruded foam is preferably, for example, from 0.1% by weight to 0.4% by weight.

  Polytetrafluoroethylene (A) is obtained by polymerizing a monomer mainly composed of tetrafluoroethylene by a known method. As long as the properties of polytetrafluoroethylene are not impaired, fluorine-containing olefins such as hexafluoropropylene and chlorotrifluoroethylene can be included as a copolymerization component. The content of the copolymer component is preferably 10% by weight or less with respect to tetrafluoroethylene. The alkyl (meth) acrylate polymer (B) having 5 to 30 carbon atoms is obtained by polymerizing a monomer containing an alkyl (meth) acrylate having 5 to 30 carbon atoms by radical polymerization or ionic polymerization. is there. Specific examples of the alkyl (meth) acrylate having 5 to 30 carbon atoms include cyclohexyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. These monomers can be used alone or in admixture of two or more. Examples of the monomer copolymerizable with an alkyl (meth) acrylate having 5 to 30 carbon atoms include styrene monomers such as styrene, p-methylstyrene, and α-methylstyrene; carbon such as methyl (meth) acrylate 1 to 4 alkyl (meth) acrylate monomers; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl acetate and vinyl butyrate Examples thereof include vinyl carboxylate monomers such as ethylene; olefin monomers such as ethylene, propylene and isobutylene; and diene monomers such as butadiene and isoprene. These monomers can be used alone or in admixture of two or more.

  The weight ratio of the alkyl (meth) acrylate polymer (B) / polytetrafluoroethylene (A) having 5 to 30 carbon atoms is preferably 0.2 or more, and more preferably 0.5 or more. If the weight ratio of (B) / (A) is less than 0.2, the dispersibility of polytetrafluoroethylene may be lowered.

(Nuclear agent)
As the nucleating agent, a known substance (for example, talc) can be appropriately selected and used. As the nucleating agent, it is preferable to use a powder. The content of the nucleating agent with respect to the entire extruded foam is not particularly limited as long as the extruded foam is within a range. For example, the content range is preferably 0.1 wt% or more and 3 wt% or less.

  Other additives include foaming aids, reinforcing materials, fillers, softeners, processing aids, activators, hygroscopic agents, flame retardants, mold release agents, etc., all of which can be applied to the present invention.

Thus, since the extruded foam of the first embodiment is a component that is friendly to the natural environment, starch and / or vegetable cellulose as its main component, not only the manufacturing and procurement process of the main component, but also extruded foam. In the body manufacturing process, it can be said to be friendly to the natural environment.

  Moreover, when it is set as the composition of this 1st embodiment, it becomes possible to make favorable the surface smoothness mentioned later, a melt | fusion property, the sharpness of an edge, and a foaming state with sufficient balance.

  (Method for producing extruded foam)

As shown in FIG. 1, the method 2 for producing an extruded foam includes a mixture preparation step 10 for preparing a mixture M1 containing starch and / or vegetable cellulose A, foaming plastic B, and a predetermined additive C, and a mixture M1. Foaming agent addition step 20 for adding foaming agent F, formulation preparation step 30 for preparing powdery formulation M2 from mixture M1 to which foaming agent F has been added, and extrusion foaming for formulation M2 An extrusion foaming step 40 to be performed.

It is preferable that the starch and / or vegetable cellulose A, the foaming plastic B and the predetermined additive C used in the mixture preparation step 10 are each in the form of powder or granules. The additive F used in the foaming agent addition step 20 is preferably liquid at normal temperature. Thereby, in the mixture preparation step 10, the foaming agent addition step 20, and the formulation preparation step 30, each component can be uniformly dispersed.

  The mixture preparation step 10, the foaming agent addition step 20, and the formulation preparation step 30 can be performed using a mixing device (for example, a Henschel mixer) or a mixing part of a twin screw extruder. Moreover, the extrusion foaming step 40 is performed using an extrusion apparatus (for example, a twin screw extruder). In this case, 30 and 40 may be carried out step by step in the same extruder.

  FIG. 2A shows the kneading part 110, the die 120, and the foaming space forming part 130 in the twin-screw extruder 100. The kneading part 110 pours the raw material into the die 120 while kneading the raw material with a biaxial screw. The dice 120 are formed with strand-shaped openings 122 that form a plurality of rows in the width direction. As shown in FIG. 2B, in this embodiment, two-stage strand openings 122 are arranged in the thickness direction. The foaming space forming portion 130 is a place where the material pushed out of the strand-like opening 122 is foamed and expanded, and the foamed string-like members are fused together to define a sheet-like or plate-like outer shape. As shown in FIG. 2C, the strand-shaped opening 122 can be changed to a single or a plurality of slits 124 to produce a foam.

  In addition, the manufacturing method 2 of an extrusion foam may have the process process which processes the extrusion foam X obtained by the extrusion foaming step 40 to a defined shape.

  The extruded foam of the first embodiment was produced along Experiments A-1 to A-9 by the following method. Each experiment will be described in detail with respect to Experiment A-1, and with respect to the other experiments, only the parts different from Experiment A-1 will be described, and the description of the same parts as Experiment A-1 will be omitted.

  (Experiment A-1)

Extruded foam production method 2 (see FIG. 1) was performed in the following procedure. In the mixture preparation step 10, each component shown in Table 1 ( starch and / or vegetable cellulose, foaming plastic, and additive) is mixed with a twin screw extruder (TEX77 L / D = manufactured by Nippon Steel Co., Ltd.). 21) was added to the supply section and mixed to prepare a mixture. In addition, corn starch (Showa Sangyo Co., Ltd. Showa Kostarch) was used as starch and / or vegetable cellulose.

In the subsequent foaming agent addition step 20 and blend preparation step 30, the foaming agent shown in Table 1 is charged into the supply section of the twin-screw extruder via the quantitative supply device, and the extruder is continuously mixed. The mixture was sent to the kneading section and kneaded to obtain a blend. In this case, the temperatures of the upper cylinders C1 to C2 of the extruder were 60 to 90 ° C, the middle cylinders C3 to C4 were 100 to 140 ° C, and the lower cylinders C5 to C6 were 170 to 200 ° C. An extruded foam was obtained by the extrusion foaming step 40.

  (Experiment A-2 to A-9)

Except what was shown in Table 1, experiment A-2-A-9 was done like experiment A-1. In Experiments A-3 to A-8, polypropylene resin (Novatech PP MH4 manufactured by Nippon Polypro Co., Ltd.) and polyethylene resin (Novatech LDPE LC500 manufactured by Nippon Polyethylene Co., Ltd.) and polystyrene resin (HIPS PH-88S manufactured by Chimei Corporation) were mixed and mixed. The characteristics according to the resin blending amount were examined. In Experiment A-9, 10% of the corn starch from Experiment A-3 was replaced with paper powder, and the total amount of starch and / or vegetable cellulose was the same. As for talc, talc SW manufactured by Nippon Talc Co., Ltd., and as the modifier, polytetrafluorotoluene acrylic metamorphosis, Mitsubishi Rayon Co., Ltd., Metablen A-3000 was used.

  (Measurement / Evaluation)

  Except for Experiment A-2, an extruded foam was obtained by the method 2 for producing an extruded foam. In Experiment A-2, since no nucleating agent or modifier (particularly modifier) was contained, extrusion foaming did not work and a foam was not obtained. The following measurements and evaluations were performed on the extruded foams obtained in Experiment A-1 and Experiments A-3 to A-9. Table 1 shows the measurement results and evaluation results in each experiment.

  The obtained extruded foam was visually observed, and the characteristics of the extruded foam were evaluated based on the evaluation criteria shown in the photograph of FIG. The characteristic evaluation was made into four types: surface smoothness, fusing property, edge sharpness, and foamed state. The surface smoothness means a state of unevenness on the surface, and the smaller the unevenness, the better. The fusibility is determined by the degree of bonding of the extruded string-like foams, and those that are integrated without forming a gap inside are good. The sharpness of the edge is good when the cross-sectional shape of each string-like foam is close to a square. In the foamed state, fine air holes (foamed cells) are good inside.

  (Measurement of compression set)

  According to JIS Z 0235 (2002, packaging cushioning material-evaluation test method), the compression set of the obtained extruded foam was measured. The compression set is a value obtained by quantifying the ratio of deformation remaining after the force is completely removed after causing compression deformation.

Except for Experiment A-2, the extruded foams of the examples are mainly composed of starch and / or vegetable cellulose. For example, as foaming plastic occupying 20% to 45% of the total weight, polypropylene resin and ethylene resin In addition, by mixing a styrene resin and using a modifier (polytetrafluoroethylene acrylic modified), it is possible to form an extruded foam that is excellent in surface cosmetics and compression strain characteristics and is friendly to the natural environment. did it. The extruded foam had a smoother surface than conventional extruded foams (particularly Experiments A-3, A-5, A-6, A-9).

  Experiments A-3, A-5, A-6, A-8, A- in which the ratio of the total weight of the ethylene-based resin and / or styrene-based resin to the entire foaming plastic is 20% or more and 40% or less No. 9 is preferable because the compression set is small and the balance between the evaluation characteristics is excellent. In addition, when the ratio of the total weight of the ethylene-based resin and / or the styrene-based resin is less than 20% or more than 40% of the entire foamed plastic, as in Experiments A-1, A-4, and A-7, Although the compression set became large or the extrusion state deteriorated, there were cases where it was somewhat undesirable, but the overall quality was within an acceptable range.

  Moreover, Experiment A-3, A-5, A-6, A-8 that the ratio of the total weight of ethylene resin and / or a styrene resin is 5% or more and 15% or less with respect to the whole foam. As shown in A-9, the compression set was small, and the balance of the evaluation characteristics was excellent. In particular, Experiments A-3, A-5, A-6, and A-9 in which the ratio of the total weight of the ethylene-based resin and / or styrene-based resin is less than 15% are preferable because the balance of the evaluation characteristics is further excellent. As a result.

In addition, it was found that even if a part of corn starch was replaced with paper powder (paper pulp cellulose) as starch and / or vegetable cellulose, a product satisfying the characteristics could be obtained (Experiment A-9). In particular, if the paper dust is 30% by weight or less, the overall quality is not adversely affected. Therefore, it can be said that such an extruded foam is suitable for packaging materials such as expensive gift products and cushioning materials in addition to the existing market.

  <Second embodiment>

The second embodiment of the present invention will be described below. In the second embodiment, a sheet-like or plate-like extruded foam (hereinafter referred to as an extruded foam) having a foamed plastic as a main component and starch and / or vegetable cellulose as a subcomponent is established.

(Extruded foam)
The extruded foam includes a main component, a foaming plastic, a foaming agent, a modifier, and an additive.

(Main component: Plastic for foaming)
Examples of the foaming plastic include polypropylene, styrene resin (eg, polystyrene, high impact polystyrene, ABS, etc.), ethylene resin (eg, high density polyethylene, low density polyethylene, ethylene vinyl acetate copolymer resin, etc.), polyester, and the like. From the viewpoint of ease of production, polypropylene and polystyrene are mainly used.

As the definition of the main component, it means here that the weight ratio of the foaming plastic is larger than that of starch and / or vegetable cellulose. For example, the content of the foaming plastic with respect to the entire extruded foam is, for example, 50% by weight. % Or more is preferable.

  Further, the ratio of the total weight of the ethylene resin and / or styrene resin in the foaming plastic is preferably 40% or more, more preferably 50% or more. Moreover, it is preferable that the ratio of the total weight of ethylene-type resin and / or styrene-type resin with respect to the whole extrusion foam is 30% or more, More preferably, you may be 40% or more.

( Starch and / or vegetable cellulose)
Examples of the starch and / or vegetable cellulose component include starch (for example, corn starch, tapioca starch, potato starch, glutinous rice starch, wheat starch), paper pulp and the like. In addition, it is preferable that government-made postcard waste paper is not included.

The content of starch and / or vegetable cellulose in the entire extruded foam is preferably 20% by weight or more, and more preferably 40% by weight or less. The upper limit of the content of starch and / or vegetable cellulose relative to the entire extruded foam is not particularly limited as long as it is within a range where an extruded foam can be obtained in relation to the content of other components.

Moreover, the upper limit of the content of starch and / or vegetable cellulose relative to the foaming plastic is not particularly limited as long as it does not exceed the content of the foaming plastic as long as an extruded foam is obtained.

(Foaming agent)
As the foaming agent, known organic and inorganic foaming agents can be appropriately selected and used. However, in the case of an organic foaming agent, aspects such as explosion-proof management, ensuring product safety, and environmental protection, etc. Is not preferable. Therefore, it is preferable to use an inorganic foaming agent. Examples of the inorganic foaming agent include water, air, carbon dioxide, nitrogen, argon, helium, and the like, but it is preferable to use water because it can be used in an open system in the atmosphere.

  The content of the foaming agent with respect to the entire extruded foam is not particularly limited as long as it is within a range where an extruded foam can be obtained. For example, the content range is preferably 1% by weight to 8% by weight, and more preferably 3% by weight to 6% by weight.

(Additive)
Examples of the additive include a modifier, a nucleating agent, a coloring material, a deodorant, and an antibacterial agent.

Hereinafter, for convenience of explanation, a mixture of starch and / or vegetable cellulose, foaming plastic, and additives is referred to as a mixture.

(Modifier)
The modifier is for improving the melt tension of the mixture (in particular, starch and / or vegetable cellulose and foaming plastic) and improving the compatibility in the mixture. The modifier is an acrylic modified product of polytetrafluoroethylene, more specifically, a polytetrafluoroethylene (A) and an alkyl (meth) acrylate polymer (B) having 5 to 30 carbon atoms. As a specific example, there is Metabrene A3000 manufactured by Mitsubishi Rayon Co., Ltd. The content of the modifier with respect to the entire extruded foam is preferably, for example, from 0.1% by weight to 0.4% by weight.

  Polytetrafluoroethylene (A) is obtained by polymerizing a monomer mainly composed of tetrafluoroethylene by a known method. As long as the properties of polytetrafluoroethylene are not impaired, fluorine-containing olefins such as hexafluoropropylene and chlorotrifluoroethylene can be included as a copolymerization component. The content of the copolymer component is preferably 10% by weight or less with respect to tetrafluoroethylene. The alkyl (meth) acrylate polymer (B) having 5 to 30 carbon atoms is obtained by polymerizing a monomer containing an alkyl (meth) acrylate having 5 to 30 carbon atoms by radical polymerization or ionic polymerization. is there. Specific examples of the alkyl (meth) acrylate having 5 to 30 carbon atoms include cyclohexyl (meth) acrylate and 2-ethylhexyl (meth) acrylate. These monomers can be used alone or in admixture of two or more. Examples of the monomer copolymerizable with an alkyl (meth) acrylate having 5 to 30 carbon atoms include styrene monomers such as styrene, p-methylstyrene, and α-methylstyrene; carbon such as methyl (meth) acrylate 1 to 4 alkyl (meth) acrylate monomers; vinyl cyanide monomers such as acrylonitrile and methacrylonitrile; vinyl ether monomers such as vinyl methyl ether and vinyl ethyl ether; vinyl acetate and vinyl butyrate Examples thereof include vinyl carboxylate monomers such as olefin monomers such as ethylene, propylene and isobutylene; diene monomers such as butadiene and isoprene. These monomers can be used alone or in admixture of two or more.

  The weight ratio of the alkyl (meth) acrylate polymer (B) / polytetrafluoroethylene (A) having 5 to 30 carbon atoms is preferably 0.2 or more, and more preferably 0.5 or more. If the weight ratio of (B) / (A) is less than 0.2, the dispersibility of polytetrafluoroethylene may be lowered.

(Nuclear agent)
As the nucleating agent, a known substance (for example, talc) can be appropriately selected and used. As the nucleating agent, it is preferable to use a powder. The content of the nucleating agent with respect to the entire extruded foam is not particularly limited as long as the extruded foam is within a range. For example, the content range is preferably 0.1 wt% or more and 3 wt% or less.

  Other additives include foaming aids, reinforcing materials, fillers, softeners, processing aids, activators, hygroscopic agents, flame retardants, mold release agents, etc., all of which can be applied to the present invention.

The extruded foam according to the second embodiment can obtain a sheet-like or plate-like foam by extrusion molding without adopting a conventional bead method due to its composition. In particular, since some of them contain starch and / or vegetable cellulose that are friendly to the natural environment, they are also friendly to the natural environment in the manufacturing process of the extruded foam.

  In addition, when the composition of the second embodiment is used, it becomes possible to improve the surface smoothness, fusing property, edge sharpness, and foaming state, which will be described later, in a good balance.

(Method for producing extruded foam)
As shown in FIG. 1, the method 2 for producing an extruded foam is a mixture preparation for preparing a mixture M1 containing starch and / or vegetable cellulose A, a foaming plastic B as a main component, and a predetermined additive C. Step 10, foaming agent addition step 20 for adding foaming agent F to mixture M1, formulation preparation step 30 for preparing powdered formulation M2 from mixture M1 to which foaming agent F has been added, and formulation M2 And an extrusion foaming step 40 for performing extrusion foaming.

It is preferable that the starch and / or vegetable cellulose A, the foaming plastic B, and the predetermined additive C used in the mixture preparation step 10 are each in the form of powder or granules. The additive F used in the foaming agent addition step 20 is preferably liquid at normal temperature. Thereby, in the mixture preparation step 10, the foaming agent addition step 20, and the formulation preparation step 30, each component can be uniformly dispersed.

  The mixture preparation step 10, the foaming agent addition step 20, and the formulation preparation step 30 can be performed using a mixing device (for example, a Henschel mixer) or a mixing part of a twin screw extruder. Moreover, the extrusion foaming step 40 is performed using an extrusion apparatus (for example, a twin screw extruder). In this case, 30 and 40 may be carried out step by step in the same extruder.

  FIG. 2A shows the kneading part 110, the die 120, and the foaming space forming part 130 in the twin-screw extruder 100. The kneading part 110 pours the raw material into the die 120 while kneading the raw material with a biaxial screw. The dice 120 are formed with strand-shaped openings 122 that form a plurality of rows in the width direction. As shown in FIG. 2B, in this embodiment, two-stage strand openings 122 are arranged in the thickness direction. The foaming space forming portion 130 is a place where the material pushed out of the strand-like opening 122 is foamed and expanded, and the foamed string-like members are fused together to define a sheet-like or plate-like outer shape. As shown in FIG. 2C, the strand-shaped opening 122 can be changed to a single or a plurality of slits 124 to produce a foam.

  In addition, the manufacturing method 2 of an extrusion foam may have the process process which processes the extrusion foam X obtained by the extrusion foaming step 40 to a defined shape.

  The extruded foam of the second embodiment was produced along Experiments B-1 to B-4 by the following method. Each experiment will be described in detail with respect to Experiment B-1, and with respect to the other experiments, only the parts different from Experiment B-1 will be described, and the description of the same parts as Experiment B-1 will be omitted.

  (Experiment B-1)

Extruded foam production method 2 (see FIG. 1) was performed in the following procedure. In the mixture preparation step 10, each component shown in Table 1 ( starch and / or vegetable cellulose and foaming plastics and additives as main components) is mixed with a twin-screw extruder (TEX77 manufactured by Nippon Steel Co., Ltd.) via a quantitative supply device. L / D = 21) was charged and mixed to prepare a mixture. In addition, corn starch (Showa Sangyo Co., Ltd. Showa Kostarch) was used as starch and / or vegetable cellulose.

In the subsequent foaming agent addition step 20 and blend preparation step 30, the foaming agent shown in Table 1 is charged into the supply section of the twin-screw extruder via the quantitative supply device, and the extruder is continuously mixed. The mixture was sent to the kneading section and kneaded to obtain a blend. In this case, the temperatures of the upper cylinders C1 to C2 of the extruder were 60 to 90 ° C, the middle cylinders C3 to C4 were 100 to 140 ° C, and the lower cylinders C5 to C6 were 170 to 200 ° C. An extruded foam was obtained by the extrusion foaming step 40.

(Experiments B-2 to B-4)
Except what was shown in Table 2, experiment B-2-B-4 was done like experiment B-1. As foaming plastics as the main component, polypropylene resin (Novatech PP MH4 manufactured by Nippon Polypro Co., Ltd.) and polyethylene resin (Novatech LDPE LC500 manufactured by Nippon Polyethylene Co., Ltd.) and polystyrene resin (HIPS PH-88S manufactured by Chimei Corporation) are blended in varying amounts. The characteristics according to the resin blending amount were examined. As for talc, talc SW manufactured by Nippon Talc Co., Ltd., and as the modifier, polytetrafluorotoluene acrylic metamorphosis, Mitsubishi Rayon Co., Ltd., Metablen A-3000 was used.

  (Measurement / Evaluation)

  In all the experiments, an extruded foam was obtained by the method 2 for producing an extruded foam. The following measurements and evaluations were performed on the extruded foams obtained in Experiments B-1 to B4. Table 1 shows the measurement results and evaluation results in each experiment.

  (Measurement of compression set)

  According to JIS Z 0235 (2002, cushioning material for packaging-evaluation test method), the compression set of the obtained extruded foam was measured. The compression set is a numerical value of a ratio of deformation remaining after the force is completely removed after causing the compression deformation.

The extruded foam of the example contains foamable plastic as a main component, for example, contains starch and / or vegetable cellulose occupying 20% or more and 45% or less of the total weight, and as the foamable plastic, polypropylene resin is used. By mixing ethylene-based resin and / or styrene-based resin and using a modifier (acrylic modified polytetrafluoroethylene), it is possible to form an extruded foam that is excellent in surface cosmetics and compression strain characteristics and is friendly to the natural environment. We were able to. The extruded foam had a smoother surface than the conventional extruded foam (Experiment B-1, B-2, B-3).

  In particular, as the foamable plastic, a mixture of polypropylene resin, ethylene resin, and / or styrene resin was excellent in all properties (Experiment B-3).

  Moreover, when the styrenic resin was included in the plastic for foaming, the other evaluation characteristics excluding the compression set became good with good balance (Experiments B-2 and B-3). On the other hand, when only a styrenic resin was contained in the polypropylene resin, a tendency to easily reduce the compression set was seen, but since the extrusion characteristics were good, such an extruded foam was added to the existing market, It can be said that it is particularly suitable for packaging materials such as expensive gift products and cushioning materials.

  It should be noted that the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

2 Extruded Foam Manufacturing Method 10 Mixture Preparation Step 20 Foaming Agent Addition Step 30 Compound Preparation Step 40 Extrusion Foaming Step

Claims (4)

Is molded into a sheet or plate, a starch and vegetable cellulose is the main component, a foaming plastic which comprises polypropylene, wherein the acryl-modified product of polytetrafluoroethylene, wherein the foamed plastic and the starch and vegetable cellulose Using a raw material obtained by mixing a modifier for a mixture containing
The content of the main component in the raw material is 100 wt% or more and 350 wt% or less with respect to the foaming plastic,
Using 3 to 8% by weight of water as a blowing agent with respect to the whole of the raw material,
The foaming plastic is a mixture of polypropylene resin, ethylene resin and / or styrene resin,
In the starch and vegetable cellulose, pulp and paper cellulose is contained at 30% by weight or less,
The raw material is formed into a sheet shape or a plate shape by passing through the openings of a die having a plurality of openings in the width direction and fusing together a plurality of string-like members that foam through the openings. The manufacturing method of the sheet-like or plate-like extrusion foam containing the plant-derived component to do. The foaming occupied in plastic, the proportion of the total weight of the ethylene-based resin and / or the styrene resin is sheet containing plant-derived components according to claim 1, characterized in that 20% to 40% Of manufacturing a sheet-like or plate-like extruded foam. The plant-derived component according to claim 1 or 2 , wherein a ratio of a total weight of the ethylene resin and / or the styrene resin is 5% or more and 15% or less with respect to the whole foam. The manufacturing method of the sheet-like or plate-like extrusion foam containing A. The acrylic varying biological polytetrafluoro toluene, according to any one of claims 1 to 3, characterized in that it comprises the whole against 0.1% or more by weight of the sheet-like or plate-like extruded foam A method for producing a sheet-like or plate-like extruded foam containing a plant-derived component.

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