JP2022073161A - Woody base material and decorative material - Google Patents

Abstract

To provide a woody base material which is excellent in mechanical strength, water resistance and can be used as, for example, a substrate material for floor, wall or the like and as fittings, furniture or the like, and to provide a decorative material using that base material.SOLUTION: Disclosed is a woody base material 20 which is formed by heating and pressurizing a raw material mixture 40 including a fine particle-like or chip-like woody material 41, a fine particle-like thermoplastic resin composition 42 and a water adsorbent 43. The density of the woody base material 20 is in a range of 0.65 to 1.2 g/cc, and the content of the water adsorbent 43 is in the range of 2 to 15 pts.mass based on 100 pts.mass of total of the woody material 41 and thermoplastic resin composition 42. In the raw material mixture 40, the mass ratio of woody material 41 to thermoplastic resin composition 42 (woody material 41/thermoplastic resin composition 42) is in the range from 95/5 to 60/40. Besides, the density of the woody base material 20 may be in the range from 0.95 to 1.2 g/cc. The water adsorbent 43 may be zeolite, and the woody material 41 may include a mushroom bed in the raw material.SELECTED DRAWING: Figure 1

Description

The present invention relates to a wood base material used for, for example, a base material for floors and walls, fittings, furniture, etc., and having excellent mechanical strength and water resistance, and a decorative material using the same.

As the adhesive for the wood substrate, a urea resin adhesive, a melamine resin adhesive, and a phenol resin adhesive are usually used together with a curing agent containing formaldehyde.
Since formaldehyde is a harmful substance that causes sick house syndrome, its emission from wood substrates has become a problem, and various measures to reduce the amount of emission have been studied, but it cannot be completely suppressed.
On the other hand, as an adhesive that does not contain formaldehyde, an adhesive containing powdered saccharides and powdered polycarboxylic acid as main components is used, which is mixed with plant fibers and molded by heating and pressure. A method for manufacturing a fiber board has been proposed (see Patent Document 1, paragraph "0017" of the specification).
Further, a method for producing a laminate containing a wood base material using an adhesive composed of polyvinyl alcohol and water has been proposed (see Patent Document 2, paragraph "0015" in the specification and FIG. 1).

Japanese Unexamined Patent Publication No. 2016-55620 Japanese Patent No. 5553279

However, the above-mentioned wood substrate using the conventional adhesive has not been practically sufficient in mechanical properties such as bending strength and water resistance.
The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a wood base material having excellent mechanical strength and water resistance and a decorative material using the wood base material.
As a result of diligent studies to solve the above-mentioned problems, the inventor makes the powder mixture contain a water adsorbent in a wood base material formed by heating and pressurizing a wood material and a powder mixture of a thermoplastic resin composition. As a result, it was found that the above-mentioned problems could be solved, and the present invention was reached.

The wood-based material according to one aspect of the present invention is formed by heating and pressurizing a raw material mixture containing a powder-like or chip-like wood-based material, a powder-like thermoplastic resin composition, and a water adsorbent. It is a wood-based material, the density of the wood-based material is 0.65 to 1.2 g / cc, and the content of the water-adsorbing material is 100 in total of the wood-based material and the thermoplastic resin composition. It is 2 to 15 parts by mass with respect to the mass ratio, and the mass ratio of the wood material to the thermoplastic resin composition is 95/5 to 60/40.
Further, the wood substrate according to one aspect of the present invention is characterized in that the density is 0.95 to 1.2 g / cc.
The wood base material according to one aspect of the present invention is characterized in that the water adsorbent is zeolite.
The wood-based material according to one aspect of the present invention is characterized in that the wood-based material contains a fungal bed as a raw material.

The decorative material according to one aspect of the present invention is a wood-based material formed by heating and pressurizing a raw material mixture containing a powder-like or chip-like wood-based material, a powder-like thermoplastic resin composition, and a water adsorbent. It is a decorative material using a base material, and the content of the water adsorbent is 2 to 15 parts by mass with respect to a total of 100 parts by mass of the wood material and the thermoplastic resin composition, and the wood base. It is characterized in that a design layer having a design property is laminated on the material.

According to one aspect of the present invention, it is possible to provide a wood base material having excellent mechanical strength and water resistance and a decorative material using the same.

It is a schematic diagram of the raw material mixture which concerns on Embodiment 1. FIG. FIG. 3 is a schematic cross-sectional view of the decorative material according to the first embodiment.

(Embodiment 1)
Embodiment 1 of the present invention will be described below with reference to the drawings.
Here, the drawings are schematic, and the relationship between the thickness and the plane dimensions, the ratio of the thickness of each layer, and the like are different from the actual ones. Further, the embodiments shown below exemplify a configuration for embodying the technical idea of the present invention, and the technical idea of the present invention describes the materials, shapes, structures, etc. of the constituent parts as follows. It is not specific to things. The technical idea of the present invention may be modified in various ways within the technical scope specified by the claims described in the claims.

(Cosmetic material 10)
In FIG. 2, 10 is a decorative material, and the decorative material 10 is used in a wide range of applications such as a base material for floors and walls, fittings, furniture, and the like.
As shown in FIG. 2, the decorative material 10 is composed of the following layers.
The following layers will be described later.
(1) Wood base material 20
(2) Design layer 30
The decorative material 10 is not limited to the above (1) and (2), and the surface of the design layer 30 may be coated with a top coat or embossed.

(Wood base material 20)
The wood base material 20 serves as a support for the decorative material 10. Specifically, as shown in FIG. 1, (1) powder or chip-shaped wood material 41 and (2) powder. It is formed by heating and pressurizing a raw material mixture 40 containing a body-shaped thermoplastic resin composition 42 and (3) a water adsorbent 43.
There is generally no definition of size or shape in the above-mentioned "powder-like" and "chip-like", but in the first embodiment, it is assumed that the size is in the range of about several tens of microns to several centimeters. There is.
The wood base material 20 can be put into practical use as a decorative material 10 by itself.
That is, as shown in FIG. 2, the wood base material 20 may be used as a decorative material 10 by laminating a design layer 2 such as paper or a film to which a design such as a pattern is imparted in order to impart design.

(Design layer 30)
The design layer 30 is located on the surface of the wood base material 20 and imparts designability, and is appropriately provided as necessary.

(Main features of wood base material 20)
The main features of the wood base material 20 are as follows.
(1) The density of the wood substrate 20 is 0.65 to 1.2 g / cc.
If the density of the wood substrate 20 is less than 0.65 g / cc, the substrate density is insufficient and the mechanical strength is inferior. When the density exceeds 1.2 g / cc, water vapor tends to stay and the base material is easily deformed. Further, it is considered that the deformed base material has voids inside, and not only the appearance but also the mechanical strength and water resistance are easily impaired.
Further, it is desirable that the density of the wood substrate 20 is 0.95 to 1.2 g / cc.
If the density of the wood substrate 20 is less than 0.95 g / cc, the mechanical strength deteriorates.

(2) The content of the water adsorbent 43 is 2 to 15 parts by mass with respect to 100 parts by mass in total of the wood material 41 and the thermoplastic resin composition 42.
If the content of the water adsorbent 43 is less than 2 parts by mass, the effect of suppressing deformation of the wood base material 20 cannot be sufficiently obtained, and if it exceeds 15 parts by mass, the mechanical strength and water resistance of the wood base material 20 are obtained. Sex is significantly reduced.

(3) In the raw material mixture 40, the mass ratio of the wood material 41 to the thermoplastic resin composition 42 (wood material 41 / thermoplastic resin composition 42) is 95/5 to 60/40.
If the mass ratio (wood material 41 / thermoplastic resin composition 42) is less than 95/5, the thermoplastic resin composition 42 is insufficient and the mechanical properties are inferior. If the mass ratio exceeds 60/40, the mechanical strength is inferior.

(4) Zeolite is desirable as the water adsorbent 43.
For example, if "zeolite" is replaced with "silica gel", the deformation of the base material is aggravated.
(5) It is desirable that the wood-based material 41 contains a fungal bed as a raw material.
When the wood material 41 contains a fungus bed, a large amount of used fungus bed generated during mushroom cultivation can be utilized for the wood base material 20, and the fungus bed can be recycled.

(Wood-based material 41)
Examples of the wood material 41 include wood flour, wood fiber, and crushed wood into chips, and thinned wood, ogre flour, waste wood, and the like can also be used as raw materials. In addition to wood, bamboo, hemp, palm fiber, walnut shell, and other materials containing a cellulose component similar to wood can be candidates.

(Raw material of wood-based material 41)
As a raw material for the wood-based material 41, a used fungal bed generated in large quantities during mushroom cultivation is suitable. The fungal bed is a medium used for mushroom cultivation, which is a mixture of wood chips and ogre flour with nutrients such as biomass and rice bran. It is estimated to be promising as biomass, but the current situation is that recycling has not progressed.

(Mass ratio of wood material 41 and thermoplastic resin composition 42)
The mass ratio of the wood material 41 and the thermoplastic resin composition 42 is in the following range.
Wood-based material 41 / Thermoplastic resin composition 42 = 95/5 to 50/50
The mass ratio is preferably in the range of 95/5 to 60/40.
If the content of the wood-based material 41 is larger than this range, sufficient bending strength and water resistance cannot be imparted to the wood-based material 20. On the other hand, if the content of the wood material 41 is smaller than this range, the wood base material 20 is likely to be deformed during heating and pressurization, which is not preferable.

(Thermoplastic Resin Composition 42)
The thermoplastic resin contained in the thermoplastic resin composition 42 can be used as a single type or a mixture of a plurality of types from candidates such as polyethylene L, polyamide, polyolefin, ethylene / propylene / diene rubber, ethylene vinyl acetate, and silicone rubber. However, it is preferable to contain polyethylene in terms of mechanical strength and water resistance of the wood substrate 20.
The polyethylene is not particularly limited, and includes high-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, linear low-density polyethylene, and the like. It is appropriately selected from existing materials in consideration of the reactivity at the time of heating and pressurization, the fluidity of the raw material mixture, and the like.

(Mixing of acid-containing resin)
The thermoplastic resin composition 42 may contain an acid-containing resin in order to improve the adhesiveness of the wood material 41 to the thermoplastic resin.
For example, maleic anhydride-modified polyethylene, polyprolene maleic anhydride and the like, maleic anhydride-modified polyolefin, ethylene (meth) acrylic acid copolymer, and itaconic anhydride-modified polyethylene can be used.
These are acid-modified polymers, and may be either a polyolefin resin graft-modified with a carboxylic acid or a carboxylic acid anhydride, or a copolymer of an olefin and an acrylic acid, maleic anhydride, or the like.

(Mixing of organic peroxide)
The thermoplastic resin composition 42 may contain an organic peroxide in order to crosslink the thermoplastic resin during hot pressing in forming the substrate.
In addition, the thermoplastic resin may improve the strength and water resistance of the wood substrate by cross-linking. For example, it is appropriately selected and used from existing materials such as peroxyketal, dialkyl peroxide, diacyl peroxide, and peroxyester in consideration of reactivity and stability.

(Preparation of Thermoplastic Resin Composition 42)
The thermoplastic resin composition 42 can be produced by various known methods. For example, a uniaxial kneader or a batch type kneader is used to heat and knead the thermoplastic resin and other raw materials, and then the machine. It can be produced by pulverizing by a method such as target pulverization or freeze pulverization.

(Moisture Adsorbent 43)
The water adsorbent 43 is used to suppress deformation of the base material during formation of the wood base material.
In the hot press of the raw material mixture 40, water vapor mainly generated from the wood material 41 stays inside, and when the press is released, the water vapor is suddenly released to the outside, which may cause deformation of the base material, which is fatal. It leads to deterioration of quality.
In particular, when trying to produce a wood substrate having a high density aiming at high strength, water vapor tends to stay and the substrate is likely to be deformed.
It is considered that the deformed base material has voids inside, and not only the appearance but also the mechanical strength and water resistance are easily impaired.
Specifically, as the water adsorbent 43, powders of inorganic oxides such as silica gel, activated alumina, diatomaceous earth, and zeolite can be used, but zeolite having excellent water adsorption performance even at high temperature during hot pressing is particularly preferable. ..

(Amount of water adsorbent 43 blended)
The blending amount of the water adsorbent 43 is 2 to 15 parts by mass with respect to 100 parts by mass of the total of the wood material and the thermoplastic resin composition. If the blending amount is less than 2 parts by mass, the effect of suppressing deformation of the wood base material 20 cannot be sufficiently obtained, and if it exceeds 15 parts by mass, the mechanical strength and water resistance of the wood base material 20 are significantly lowered. ..

(Method of heating and pressurizing the raw material mixture 40)
Various known methods can be used for heating and pressurizing the raw material mixture 40, but press molding using a frame mold is preferable.
The heating temperature is usually 120 ° C. to 250 ° C., and needs to be equal to or higher than the melting point of the thermoplastic resin, but if it exceeds 250 ° C., thermal deterioration of the wood material 41 may occur remarkably.
The pressurizing pressure is usually 10 to 200 kgf / cm ² , and a value appropriately set according to the desired density of the wood substrate is used.
The density and shape of the wood substrate 20 are appropriately determined depending on the intended use, but the density is preferably 0.65 to 1.2 g / cc, more preferably 0.95 to 1.2 g / cc.

(Manufacturing method of wood base material 20)
First, the method for producing the thermoplastic resin composition 42 is as follows.
(1) Low-density polyethylene resin (LDPE): 90 parts by mass (2) Acid-modified polyolefin resin: 10 parts by mass The above (1) to (2) are heat-kneaded with a batch-type kneader and then mechanically crushed. To obtain a powdery thermoplastic resin composition 42.
Next, for the wood-based material 41, the used fungal bed is washed and dried to obtain the wood-based material 41.
The water adsorbent 43 was added and mixed at a predetermined mass ratio as shown in FIG. 1 to obtain a raw material mixture 40.
The wood base material 20 is manufactured by introducing the raw material mixture 40 into an aluminum mold and heating and pressurizing it with a hot press device.
(Manufacturing method of decorative material 10)
As shown in FIG. 2, the design layer 30 is laminated on the surface of the manufactured wood base material 20, and the decorative material 10 is manufactured.

The main conditions of Example 1 are as shown in Table 1 below.
In addition to Example 1, the conditions of Examples 2 to 6 and Comparative Examples 1 to 5 are also shown in Table 1 below.

The thermoplastic resin composition of Example 1 is as follows.
(1) Low-density polyethylene resin (LDPE): 90 parts by mass (2) Acid-modified polyolefin resin (trade name: Umex 100TS, manufactured by Sanyo Kasei Kogyo Co., Ltd.): 10 parts by mass The above (1) to (2) are After heat-kneading with a batch-type kneading device, the mixture was mechanically pulverized to obtain a powdery "thermoplastic resin composition".
Next, for the wood material, the used fungus bed was washed and dried, and for the water adsorbent, powdered silica gel (trade name: Microdo, manufactured by Tokai Chemical Industry Co., Ltd.) was used. A raw material mixture was obtained by mixing at a mass ratio of thermoplastic resin composition / moisture adsorbent = 85/15/5.
The wood substrate of Example 1 was obtained by introducing this raw material mixture into an aluminum mold and heating and pressurizing it with a hot press device (pressing conditions: 100 kgf / cm ² , 200 ° C. for 10 minutes, substrate). Material thickness: 10 mm).
The substrate density is 0.9 g / cc.

(Example 2)
In Example 2, the mass ratio of the raw material mixture (wood material / thermoplastic resin composition / moisture adsorbent) was changed from "85/15/5" of Example 1 to "85/15/10", and the mass ratio thereof was changed. The wood-based substrate of the second example was obtained by the same method as in the first embodiment except for the above.
The substrate density is 0.9 g / cc.
(Example 3)
In Example 3, the "powdered silica gel" of Example 2 was replaced with "powdered zeolite (trade name: Zeolite A4, manufactured by Tosoh Corporation)", and other than that, it was carried out in the same manner as in Example 2. The wood substrate of Example 3 was obtained.
The substrate density is 0.9 g / cc.

(Example 4)
In Example 4, the substrate density "0.9 g / cc" of Example 3 was changed to "1.1 g / cc", and other than that, the same method as in Example 3 was used to make the wood base of Example 4. I got the wood.
(Example 5)
In Example 5, the mass ratio of the raw material mixture (wood material / thermoplastic resin composition / moisture adsorbent) was changed from "85/15/10" in Example 4 to "85/15/5". A wood-based substrate of Example 5 was obtained by the same method as in Example 4 except for the above.
The substrate density is 1.1 g / cc.
(Example 6)
In Example 6, the mass ratio of the raw material mixture (wood material / thermoplastic resin composition / moisture adsorbent) was changed from "85/15/10" in Example 4 to "60/40/10". A wood-based substrate of Example 6 was obtained in the same manner as in Example 4 except for the above.
The substrate density is 1.1 g / cc.

(Comparative Example 1)
In Comparative Example 1, a wood base material of Comparative Example 1 was obtained by the same method as in Example 1 except that the water adsorbent was excluded from the raw material mixture of Example 1.
The substrate density is 0.9 g / cc.
(Comparative Example 2)
In Comparative Example 2, the mass ratio (wood material / thermoplastic resin composition / moisture adsorbent) of the raw material mixture was changed from "85/15/5" of Example 3 to "85/15/20". A wood-based substrate of Comparative Example 2 was obtained by the same method as in Example 1 except for the above.
The substrate density is 0.9 g / cc.

(Comparative Example 3)
In Comparative Example 3, the mass ratio (wood material / thermoplastic resin composition / moisture adsorbent) of the raw material mixture was changed from "85/15/5" of Example 2 to "85/15/20". A wood-based substrate of Comparative Example 3 was obtained by the same method as in Example 1 except for the above.
The substrate density is 0.9 g / cc.
(Comparative Example 4)
In Comparative Example 4, the substrate density "1.1 g / cc" of Comparative Example 1 was changed to "0.6 g / cc", and other than that, the wood group of Comparative Example 4 was used in the same manner as in Comparative Example 1. I got the wood.
(Comparative Example 5)
In Comparative Example 5, the mass ratio (wood material / thermoplastic resin composition / moisture adsorbent) of the raw material mixture was changed from "85/15/10" of Example 4 to "97/3/10". A wood-based substrate of Comparative Example 5 was obtained by the same method as in Example 4 except for the above.
The substrate density is 1.1 g / cc.

(Evaluation of wood substrate)
The physical properties of the wood substrate were evaluated on the following three points.
(1) Mechanical strength, (2) Water resistance, (3) Substrate deformation (mechanical strength)
For the mechanical strength, the bending strength was measured by a method according to JIS A5908.
The evaluation criteria for mechanical strength for measured values (unit: N / mm2) are as follows: "◎""○""△""×", and pass "◎""○""△"."X" was rejected.
◎: 18 or more (pass)
◯: 13 or more and less than 18 (pass)
Δ: 8 or more and less than 13 (pass)
×: Less than 8 (failed)

(water resistant)
For water resistance, the water absorption thickness and swelling rate were measured by a method according to JIS A5908.
The evaluation criteria for the measured value (unit:%) were as follows, with three stages of "○", "△", and "×", "○" and "△" were passed, and "×" was rejected.
○: Less than 8 (passed)
Δ: 8 or more and less than 12 (pass)
×: 12 or more (failed)

(Base material deformation)
The evaluation of the deformation of the base material is carried out by visual inspection and surface tactile sensation, and the evaluation criteria are as follows, with three stages of "○", "△" and "×". It was rejected.
◯: No deformation of the base material is observed in either appearance or tactile sensation (pass)
Δ: No deformation of the base material is observed in the appearance, but slight surface irregularities are observed from the tactile sensation (pass).
×: Surface blister is recognized from the appearance (failure)
(Evaluation results)
As for the evaluation results of the wood substrate, as shown in Table 1 above, it is Examples 1 to 6 that all of the three physical property evaluations are "passed", and Comparative Examples 1 to 5 include one or more failures. It was.

(Evaluation result of mechanical strength)
The mechanical strength was unacceptable in 5 cases from Comparative Example 1 to Comparative Example 5.
In Comparative Example 1, no water adsorbent was used in the raw material mixture, in Comparative Example 2 and Comparative Example 3, the amount of the water adsorbent was excessive, and in Comparative Example 4, the substrate density was insufficient. It can be inferred that Comparative Example 5 is caused by an insufficient amount of the thermoplastic resin composition.

(Water resistance evaluation result)
There were four cases in which the water resistance was unacceptable: Comparative Example 1 to Comparative Example 3 and Comparative Example 5.
In Comparative Example 1, no water adsorbent was used in the raw material mixture, in Comparative Example 2 and Comparative Example 3, the amount of the water adsorbent was excessive, and in Comparative Example 5, the amount of the thermoplastic resin composition was mixed. It can be inferred that the cause is lack.

(Evaluation result of substrate deformation)
The case where the base material deformation was unacceptable was one of Comparative Example 1.
It can be presumed that Comparative Example 1 is caused by the fact that the water adsorbent is not used in the raw material mixture, and the water vapor accumulated inside is not adsorbed during the hot press and is rapidly released when the press is opened. It is considered that the base material in which the base material is deformed is in a state where voids are generated inside, and the mechanical strength and water resistance of the wood base material of Comparative Example 1 described above are deteriorated, which causes the failure. Is considered to be.

(Evaluation results of Examples 1 to 6)
As for the evaluation results of Examples 1 to 6, all of the three physical property evaluations were "passed".
Comparing the evaluation results of Examples 1 to 6, all of the three physical property evaluations were "○" to "◎" in the three cases of Example 3, Example 4, and Example 6, and the implementation was carried out. Example 4 is the best mode.
There are two cases, Example 1 and Example 2, in which "Δ" is included in the evaluation result of the mechanical strength.
Since the water adsorbent was replaced with "silica gel" from "zeolite" in Example 3, it can be presumed that the deformation of the base material was deteriorated and the mechanical strength was lowered as described later.

It is one case of Example 2 that "Δ" is included in the evaluation result of water resistance.
It can be inferred that the cause was that the blending amount of the water adsorbent "silica gel" was increased from "5 parts" to "10 parts" in Example 1.
The three cases of Example 1, Example 2, and Example 5 include "Δ" in the evaluation result of the substrate deformation.

In Example 1 and Example 2, it can be inferred that the cause is that the water adsorbent was replaced with "silica gel" from "zeolite" in Example 3.
Since the amount of water adsorbed near the press temperature of "silica gel" is significantly smaller than that of "zeolite", it can be inferred that the amount of water vapor retained during pressing increases and the deformation of the base material worsens.
In Example 5, it can be inferred that the cause was that the blending amount of "zeolite" in Example 4 was reduced from "10 parts" to "5 parts".

10 Decorative material 20 Wood base material 30 Design layer 40 Raw material mixture 41 Wood material 42 Thermoplastic resin composition 43 Moisture adsorbent

Claims (5)

A wood base material formed by heating and pressurizing a raw material mixture containing a powdery or chip-shaped wood material, a powdery thermoplastic resin composition, and a water adsorbent.
The density of the wood-based material is 0.65 to 1.2 g / cc, and the content of the water-adsorbing material is 2 with respect to a total of 100 parts by mass of the wood-based material and the thermoplastic resin composition. ~ 15 parts by mass,
A wood base material having a mass ratio of the wood material to the thermoplastic resin composition of 95/5 to 60/40. The wood base material according to claim 1, wherein the density is 0.95 to 1.2 g / cc. The wood base material according to claim 1 or 2, wherein the water adsorbent is zeolite. The wood-based material according to any one of claims 1 to 3, wherein the wood-based material contains a fungal bed as a raw material. A decorative material using a wood-based base material formed by heating and pressurizing a raw material mixture containing a powder-like or chip-like wood material, a powder-like thermoplastic resin composition, and a water adsorbent.
The content of the moisture adsorbent is 2 to 15 parts by mass with respect to 100 parts by mass in total of the wood material and the thermoplastic resin composition, and a design layer having design properties is laminated on the wood base material. A decorative material characterized by being made.

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