JP6909564B2 - Flooring method - Google Patents

Description

The present invention relates to a method for producing a flooring material having a foamed resin layer containing a recycled vinyl chloride resin.

In addition to having a certain degree of flexibility and mechanical strength, the flooring material is desired to have a relatively light weight per unit area so that it can be easily transported and constructed.
As a flooring material satisfying such a condition, a vinyl chloride resin flooring material having a foam layer is known.
By the way, in recent years, recycling of various resins has been recommended in order to reduce the environmental load, and recycled vinyl chloride resin is used as a material for forming the vinyl chloride resin flooring material. The recycled vinyl chloride resin refers to a vinyl chloride resin obtained from waste materials such as scraps of vinyl chloride products and used vinyl chloride products.
However, since the content of additives such as stabilizers differs depending on the waste material used as the raw material of the recycled vinyl chloride resin, the physical properties are not stable as compared with the case where the virgin vinyl chloride resin is used. There is a problem that it is difficult to process. Therefore, even if an attempt is made to form a foamed resin layer using a material containing a chemical foaming agent that generates gas and a recycled vinyl chloride resin, it is difficult to foam at a desired magnification such as excessive foaming or non-foaming in some places, and the foaming resin layer is substantially uniform. It is not possible to form a foam layer with a large thickness.

An object of the present invention is to provide a method for producing a relatively lightweight flooring material, which has a foamed resin layer formed from a material containing a recycled vinyl chloride resin, has sufficient strength and appropriate flexibility. Is.

In the method for producing a flooring material of the present invention, a recycled vinyl chloride resin is heated and melted to form a fluid gel, and a filler, calcium carbonate, is mixed with the recycled vinyl chloride resin to change the fluid from a gel to a powder. A mixing step of obtaining an intermediate material containing a modified recycled vinyl chloride resin and a filler, and then adding an unexpanded heat-expandable microcapsule to the powdery intermediate material and mixing the mixture to obtain a molding material. It has a molding step of molding the foamed resin layer by extruding the molding material while heating it.

A preferred method for producing a flooring material of the present invention is to use the intermediate material and the above in the mixing step so that the temperature range is equal to or higher than the melting temperature of the regenerated vinyl chloride resin and lower than the expansion start temperature of the heat-expandable microcapsules. The unexpanded heat-expandable microcapsule material is mixed and heated at a temperature equal to or higher than the melting temperature of the regenerated vinyl chloride resin in the molding step.
In the preferred method for producing a floor material of the present invention, in the mixing step, the material containing the regenerated vinyl chloride resin and the filler is started to expand of the heat-expandable microcapsules at a temperature equal to or higher than the melting temperature of the regenerated vinyl chloride resin. After mixing so as to be in a temperature range lower than the temperature, the temperature is lowered to a temperature lower than the melting temperature of the regenerated vinyl chloride resin, and the unexpanded thermal expansion property is applied to the intermediate material after the temperature is lowered. The molding material is obtained by adding microcapsules and mixing again, and in the molding step, the resin is heated at a temperature equal to or higher than the melting temperature of the recycled vinyl chloride resin.

Since the production method of the present invention uses a recycled vinyl chloride resin, it is environmentally preferable, and the flooring material obtained by the production method of the present invention has sufficient strength and appropriate flexibility. Further, according to the present invention, since a substantially homogeneous foamed resin layer can be formed by containing a recycled vinyl chloride resin, a relatively lightweight flooring material can be obtained.

The plan view of the flooring material which concerns on 1st Embodiment of this invention. An enlarged cross-sectional view of the flooring material cut along the line II-II of FIG. An enlarged cross-sectional view of the flooring material according to the second embodiment (cut at a location similar to the line II-II in FIG. 1). An enlarged cross-sectional view of the flooring material according to the third embodiment (cut at a location similar to the line II-II in FIG. 1). An enlarged cross-sectional view of the flooring material according to the fourth embodiment (cut at a portion similar to the line II-II in FIG. 1). An enlarged cross-sectional view of the flooring material according to the fifth embodiment (cut at a location similar to the line II-II in FIG. 1). Enlarged reference cross-sectional view of the foamed resin layer. Schematic side view of the flooring manufacturing process.

Hereinafter, the present invention will be described with reference to the drawings as appropriate.
In the present specification, "upper surface" or "upper surface" of a layer refers to a surface or direction far from the floor surface on which the flooring material is laid, and "lower surface" or "lower surface" refers to the opposite side (floor material). Refers to the surface or direction of the floor (the side closer to the floor to be laid).
In the present specification, the numerical range represented by "~" means a numerical range including the numerical values before and after "~" as the lower limit value and the upper limit value. When a plurality of lower limit values and a plurality of upper limit values are described separately, an arbitrary lower limit value and an arbitrary upper limit value can be selected and set in a range connected by "~".
Also, please note that the dimensions such as thickness and size in each figure are different from the actual ones.

[Laminated flooring structure]
FIG. 1 is a plan view of the flooring material of the first embodiment, and FIG. 2 is an enlarged cross-sectional view of the flooring material.
As shown in FIG. 1, the flooring material 1 is formed in a long strip shape in a plan view. In the present specification, the long strip shape is a rectangular shape in which the length in one direction is sufficiently longer than the length in the other direction (the other direction is orthogonal to one direction), for example, one direction. The length of is twice or more, preferably four times or more the length in the other direction. The long strip-shaped flooring material 1 is usually wrapped in a roll and used for storage and transportation, and is cut into a desired shape and used at a construction site. However, the flooring material 1 of the present invention is not limited to a long strip-shaped sheet, and may be a tile formed in a single-wafer shape such as a square shape in a plan view (not shown).

The long strip-shaped flooring material 1 is formed to have a predetermined width such as a width of 800 mm to 4000 mm and a predetermined length, and the length thereof is, for example, 2 m to 300 m. The flooring material 1 formed in a single-wafer shape has, for example, 100 mm to 4000 mm in length and width, respectively. The single-wafered flooring material 1 is generally a square-shaped flooring material 1 having a side length of 50 cm in a plan view, but may be a rectangle or a hexagonal shape having a length of 10 cm and a width of 90 cm, and the size and shape are particularly limited. Not done.
If necessary, the upper surface of the floor material 1 may be embossed (not shown) in order to impart an uneven pattern. Further, the lower surface of the floor material 1 or the upper surface and the lower surface of the floor material 1 may be embossed, if necessary.

The flooring material 1 of the present invention has a foamed resin layer and has flexibility. As for the degree of flexibility of the flooring material 1, for example, the flooring material 1 of the present invention can be wound around a core material having a diameter of 10 cm in a roll shape.
The flooring material 1 of the present invention may be composed of only a foamed resin layer, but usually has a laminated structure including a foamed resin layer 7 and an arbitrary other layer.
For example, the flooring material 1 shown in FIG. 2 has a scratch prevention layer 2, a protective layer 3, a decorative layer 4, a resin layer 5, a first base material layer 61, a foamed resin layer 7, and a second base material layer in this order from the upper side. It is a laminated body composed of 62. Each of these layers is joined and integrated.
3 to 6 are cross-sectional views of the flooring material 1 of the second to fifth embodiments. The plan view of the flooring material 1 of the second to fifth embodiments is the same as that of FIG. 1, and is omitted.
The flooring material 1 of the second embodiment shown in FIG. 3 has a scratch prevention layer 2, a protective layer 3, a decorative layer 4, a foamed resin layer 7, a first base material layer 61, a resin layer 5, and a second layer in this order from the upper side. It is a laminated body composed of a base material layer 62. Each of these layers is joined and integrated.
The flooring material 1 of the third embodiment shown in FIG. 4 has a scratch prevention layer 2, a protective layer 3, a decorative layer 4, a resin layer 5, a first base material layer 61, a foamed resin layer 7, and a second in order from the upper side. It is a laminated body composed of a base material layer 62 and a backing layer 63. Each of these layers is joined and integrated. Examples of the backing layer 63 include an adsorption layer such as a rubber, felt, or foamed acrylic resin layer.
The flooring material 1 of the fourth embodiment shown in FIG. 5 has a scratch prevention layer 2, a protective layer 3, a decorative layer 4, a foamed resin layer 7, a first base material layer 61, a foamed resin layer 7, and a third in order from the upper side. It is a laminated body composed of two base material layers 62. Each of these layers is joined and integrated.
The floor material 1 of the fifth embodiment shown in FIG. 6 is a laminated body composed of a scratch prevention layer 2, a protective layer 3, a decorative layer 4, a foamed resin layer 7, and a second base material layer 62 in this order from the upper side. Each of these layers is joined and integrated. A backing layer may be provided on the lowermost surface of the flooring material 1 shown in FIGS. 2, 3, 5, and 6 in the same manner as in FIG.
Although not particularly shown, in the flooring material 1 of the first to fifth embodiments, at least one layer selected from the scratch prevention layer 2, the protective layer 3 and the decorative layer 4 may be omitted, and the first base material may be omitted. At least one layer selected from the layer 61 and the second base material layer 62 may be omitted.

<Foam resin layer>
The foamed resin layer 7 contains a regenerated vinyl chloride resin and heat-expandable microcapsules.
FIG. 7 is a partially enlarged cross-sectional view of only the foamed resin layer 7.
The foamed resin layer 7 has a hollow portion 7a inside. Although not particularly shown, a part of the cavity portion 7a may exist on the upper surface or the lower surface of the foamed resin layer 7. In this case, the foamed resin layer 7 corresponds to the cavity portion 7a on the upper surface or the lower surface thereof. Has a recessed portion. The cavity 7a is an innumerable space formed in the foamed resin layer 7.
The inner wall of the cavity forming the cavity 7a is formed by the outer shell 72 of the microcapsule. However, the case is not limited to the case where the inner walls of all the cavities 7a are composed of the outer shell 72 of the microcapsules. For example, as shown by reference numeral 73, the regenerated vinyl chloride resin is a part of the cavities 7a. It may also constitute the inner wall of the cavity.
The three-dimensional shape of the hollow portion 7a is not particularly limited, and examples thereof include a hollow substantially elliptical spherical shape, a hollow substantially spherical shape, and a hollow substantially rectangular parallelepiped shape. In the present invention, the "abbreviation" of the shape means a shape permitted in the technical field to which the present invention belongs. The three-dimensional "substantially elliptical sphere, substantially sphere" of the cavity portion 7a includes, for example, a shape including a convex surface or a concave concave surface in which a part of the curved surface is bulged, a shape in which a part of the curved surface is a flat surface, and the like. .. Further, the "substantially rectangular parallelepiped shape" includes, for example, a shape including a convex surface or a concave surface in which a part of a plane is bulged, a shape in which a corner portion is arcuate, and the like.
The size of the cavity 7a depends on the size of the thermally expanded microcapsules.

The foamed resin layer 7 may contain other components in addition to the regenerated vinyl chloride resin and the heat-expandable microcapsules. Other components include various additives such as plasticizers, fillers, stabilizers, processing aids, fungicides, flame retardants, UV absorbers, colorants such as pigments, antioxidants and lubricants. For example, the foamed resin layer 7 contains at least a plasticizer as an additive, or at least a plasticizer and a filler as an additive, in addition to the recycled vinyl chloride resin and the heat-expandable microcapsules.
The thickness of the foamed resin layer 7 is not particularly limited, but is, for example, 0.5 mm to 5 mm, preferably 1 mm to 3 mm.

<Scratch prevention layer>
The scratch prevention layer 2 is a layer provided together with the protective layer 3 to impart dirt removal property to the floor material 1 and further to impart wear resistance and scratch resistance to the upper surface of the floor material 1. The scratch prevention layer 2 is provided as needed. The scratch prevention layer 2 may be transparent or opaque, but is preferably transparent in order to make the design of the decorative layer 4 visible.
The scratch prevention layer 2 is formed of, for example, a resin material. The resin material is not particularly limited, but is preferably formed from a relatively hard resin layer. As the resin material of the scratch prevention layer 2, it is preferable to use a curable resin because of its good workability, and further, it is more preferable to use an ionizing radiation curable resin because it is difficult to cause thermal damage to the protective layer 3. Since it is versatile, it is more preferable to use an ultraviolet curable resin. Examples of the curable resin include thermosetting resins and resins that are cured by non-ionizing radiation, in addition to ionizing radiation curable resins such as ultraviolet curable resins. The thickness of the scratch prevention layer 2 is not particularly limited, but is, for example, 1 μm to 100 μm, preferably 5 μm to 70 μm, and more preferably 10 μm to 50 μm.

<Protective layer>
The protective layer 3 is a layer provided so that dirt adhering to the floor material 1 can be easily removed. The protective layer 3 is provided as needed. The protective layer 3 may be transparent or opaque, but is preferably transparent for the same reason as the scratch prevention layer 2.
The protective layer 3 is formed of, for example, a resin material. As the resin material, a thermoplastic resin is generally used. Examples of the thermoplastic resin include vinyl chloride resins such as vinyl chloride and vinyl chloride-vinyl acetate copolymers; polyolefin resins; urethane resins; vinyl acetate resins such as ethylene-vinyl acetate copolymers; ethylene-methacrylates. Acrylic resins such as resins; polyamide resins; ester resins; various elastomers such as olefin elastomers and styrene elastomers; rubber and the like can be mentioned. These can be used alone or in combination of two or more. A resin containing a vinyl chloride resin as a main component is preferable because it firmly bonds to the decorative layer 4, the resin layer 5, or the foamed resin layer 7. The thickness of the protective layer 3 is not particularly limited, and is, for example, 0.03 mm to 1 mm.

<Cosmetic layer>
The decorative layer 4 is a layer that imparts a design to the flooring material 1. The decorative layer 4 is provided as needed.
Examples of the decorative layer 4 include a transfer layer, a design printing layer, a design printing sheet, and a thermoplastic resin layer to which design properties are imparted. However, the decorative layer 4 is not limited to these exemplified layers, and any other layer that can express the design can be used.
The transfer layer is composed of a transfer film formed by printing a printing ink on a base material such as a release paper and solidifying it, and then peeling off the solidified printing ink. The decorative layer 4 composed of the transfer layer is formed by transferring to the lower surface of the protective layer 3 or the like. The design printing layer is composed of a layer obtained by directly printing printing ink on the lower surface of the protective layer 3 and solidifying the design printing layer. The decorative layer 4 made of a design printing sheet is formed by joining a sheet to which a design printing has been performed in advance to the lower surface of the protective layer 3 or the like. The thermoplastic resin layer to which the design property is given is a layer that can be a design itself. When the thermoplastic resin layer is (1) given a design by the color of the resin itself, (2) a colorant is mixed, and the design is given by the color of the colorant and how it is mixed. In the case, (3) resin chips are mixed, and when designability is given by the color, shape, dispersion method, etc. of the resin chips, (4) colorants having different colors and the resin chips are mixed and they are mixed. For example, when the design is given by the color and the way of mixing. The decorative layer 4 made of a thermoplastic resin layer is formed by laminating and joining the thermoplastic resin layer to the lower surface of the protective layer 3 or the like. The thickness of the decorative layer 4 is not particularly limited, but is, for example, 0.5 μm to 1 mm, preferably 0.01 mm to 0.8 mm. In particular, the thickness of the decorative layer 4 composed of the transfer layer and the design printing layer is 0.5 μm to 0.5 mm.

<Resin layer>
The resin layer 5 is a layer that constitutes the strength and weight of the flooring material 1. The resin layer 5 is provided as needed.
The resin layer 5 may or may not be foamed. The resin layer 5 in the illustrated example is not foamed (non-foamed). Examples of the material for forming the resin layer 5 include those exemplified in the above <Protective layer> column, and a resin containing a vinyl chloride resin as a main component is preferable because it firmly bonds with the decorative layer 4 and the like. .. By impregnating the resin layer 5 with a colorant such as a pigment, it is possible to form the resin layer 5 to which the design property is imparted depending on the color or mixing method of the colorant. When the resin layer 5 to which the design property is imparted is used, the decorative layer 4 may be omitted. The thickness of the resin layer 5 is not particularly limited, and is, for example, 0.05 mm to 1.0 mm, preferably 0.1 mm to 0.8 mm.

<First base material layer and second base material layer>
The first base material layer 61 and the second base material layer 62 are layers for suppressing dimensional change or warpage of the flooring material 1 due to shrinkage or expansion over time. The first base material layer 61 and the second base material layer 62 are provided as needed.
The first base material layer 61 and the second base material layer 62 are not particularly limited, but conventionally known fiber sheets such as non-woven fabric, woven fabric, paper, and felt can be used independently of each. The material of the fiber constituting the non-woven fabric or the woven fabric is not particularly limited, and examples thereof include synthetic resin fibers such as polyester and polyolefin; inorganic fibers such as glass and carbon; and natural fibers. Since the first base material layer 61 arranged in the middle in the thickness direction of the floor material 1 can particularly suppress the shrinkage and expansion of the floor material 1 over time, it is possible to use a non-woven fabric or a woven fabric containing inorganic fibers such as glass. preferable. As the second base material layer 62 arranged on the lower surface side or the lowermost surface side of the floor material 1, it is preferable to use a non-woven fabric or a woven fabric containing synthetic resin fibers because the upper warp of the floor material 1 can be suppressed. Basis weight of the first base layer 61 and the second base layer 62 is not particularly limited, each independently, for ^example, a ^{30g / m 2 ~50g / m 2} . In addition, only one of the first base material layer 61 and the second base material layer 62 may be provided.

[Manufacturing method of flooring material]
The method for producing a flooring material of the present invention includes a mixing step of mixing a material containing a recycled vinyl chloride resin and heat-expandable microcapsules, and a molding step of extruding the material while heating to form a foamed resin layer.
The method for producing a flooring material of the present invention may have other steps in addition to the mixing step and the molding step. For example, as described above, the flooring material 1 is formed on the foamed resin layer 7 from the scratch prevention layer 2, the protective layer 3, the decorative layer 4, the resin layer 5, the first base material layer 61, and the second base material layer 62. At least one selected layer is laminated. The production method of the present invention may include these laminating steps. Further, it may have an embossing process or the like.
Each of these steps may be carried out in a series on one production line, or one or more steps selected from the above steps may be carried out on one line, and the remaining steps may be carried out on the other one or more. You may go on two or more lines. In addition, one performer may perform all of the steps, or one performer may perform one or more steps selected from the steps, and the remaining steps may be performed by another. May be done by a person.
FIG. 8 is a schematic side view schematically showing each step of the flooring manufacturing method. The production line used in the production method of FIG. 8 is a case where the step of laminating each layer to the production of a long strip-shaped flooring material are performed in a series.

<Preparation process of foamed resin layer>
(Waste material processing process)
The waste material treatment step is a step of crushing the waste material of a vinyl chloride product to an appropriate size.
The waste material of the vinyl chloride product is not particularly limited as long as it is a product mainly containing a vinyl chloride resin, and examples thereof include used products and offcuts. The used products include used agricultural materials such as vinyl chloride multi-sheets for agriculture and vinyl chloride sheets for greenhouses; used building materials such as wallpaper and flooring; vinyl chloride hoses and vinyl chloride. Used industrial materials such as pipes; etc. Examples of the scrap include scraps, defective products, non-standard products and the like generated when manufacturing vinyl chloride products such as the agricultural materials, building materials and industrial materials.
Since the waste materials of the vinyl chloride products are suitable for reuse from the viewpoint of resource saving based on the protection of global resources and the viewpoint of waste reduction, further utilization is required. Among them, as agricultural materials, vinyl chloride resin sheets are widely used in agricultural facilities such as agricultural houses in order to adjust conditions such as light and temperature suitable for growing agricultural products. In particular, since it is effective for improving the efficiency of agricultural land use and adjusting the harvest time and yield, agricultural use is a field for mass consumption of vinyl chloride resin. Therefore, the reuse of used agricultural materials is particularly useful from the viewpoint of resource saving based on the protection of global resources and the viewpoint of waste reduction.
By the way, in addition to plasticizers, waste materials of vinyl chloride products include stabilizers, fungicides, lubricants, UV absorbers, light stabilizers such as hindered amine compounds, drip-proofing agents, inorganic fillers, and antifungal agents, if necessary. It contains various additives such as atomizers and colorants, and may also contain a large amount of non-woven fabric, glass fiber, sand, lint, and the like. Since the used agricultural material contains a relatively small amount of additives including an inorganic filler, it can be suitably used in the present invention.

The recovered waste material is crushed using a crusher to obtain a crushed waste material. The size of the crushed waste material is not particularly limited, but if it is too large, it takes a lot of time to melt the recycled vinyl chloride resin. For this reason, it is preferable to use the pulverized product that passes through a sieve having a mesh size of 8 mesh to 10 mesh. In this specification, the sieve is based on JISZ8801-1: 2006.
If a large amount of sand or lint is mixed in the crushed material, it is possible to remove the sand or lint from the crushed material by performing wind power separation or weight separation with a dust separator. preferable.

(Mixing process)
The mixing step is a step of mixing a material containing a regenerated vinyl chloride resin and unexpanded heat-expandable microcapsules to obtain a material for forming a foamed resin layer.
In addition, "mixing" generally means mixing two or more different substances, but in the present specification, in addition to the above general meaning, one substance is mixed for homogenization or the like. Including the case, it is called "mixed".
The pulverized product contains a regenerated vinyl chloride resin.
Along with this pulverized product, the heat-expandable microcapsules before expansion are placed in a mixing device such as a mixer to melt the pulverized product. If necessary, fillers, plasticizers, and additives other than fillers and plasticizers are placed in the mixer. Hereinafter, additives other than fillers and plasticizers will be referred to as other additives. Further, in the present invention, a good foamed resin layer can be formed even if 100% of the recycled vinyl chloride resin is used as the vinyl chloride resin component, but if necessary, a virgin vinyl chloride resin is added to the material. You may. In this specification, virgin refers to a new material that has not yet been used as a product.
As the mixing device, a conventionally known one such as a super mixer may be used.

The heat-expandable microcapsules have an outer shell made of a thermoplastic resin and an inner shell component contained in the outer shell and vaporized by heating.
In the heat-expandable microcapsules, the outer shell is softened by heating and the contained components are vaporized to push the outer shell out of the diameter, and as a result, the outer shell expands. As a result, the heat-expandable microcapsules before heating have almost no cavities inside the outer shell, but after heating, large cavities are formed inside the outer shell. In the heat-expandable microcapsules, as the heating temperature rises, the expansion of the outer shell starts and the maximum expansion of the outer shell occurs in order. Further, when the expansion of the outer shell exceeds the limit, cracks and holes are generated in the outer shell and the internal pressure is reduced, and as a result, the outer shell may be further contracted. The temperature at which the outer shell starts to expand and the temperature at which the outer shell expands to the maximum can be set according to the outer shell and the contained components of the heat-expandable microcapsules.
By using the heat-expandable microcapsules under appropriate conditions, even if a resin that is generally not suitable for foaming, such as a recycled vinyl chloride resin, is used, it has closed cells and is excellent in mechanical strength. It becomes possible to form a foamed resin layer. By using the heat-expandable microcapsules, there is an advantage that uniform closed cells can be easily introduced, which was difficult by the foaming method using a chemical foaming agent or the like. By using the heat-expandable microcapsule, a foamed resin layer in which the cavity is a closed cell can be obtained, the regenerated vinyl chloride resin can be foamed by a simple process of heating only, and the heat-expandable microcapsule There is an advantage that the thickness of the foamed resin layer can be easily controlled by adjusting the blending amount.

In producing a foamed resin layer containing a recycled vinyl chloride resin using heat-expandable microcapsules, the material for forming the foamed resin layer becomes hot in two steps, a mixing step and a molding step. Thermally expandable microcapsules that do not expand in such a mixing step and expand sufficiently in a subsequent molding step are used.
In the present invention, in the thermally expandable microcapsule, the expansion start temperature and the maximum expansion temperature of the outer shell are higher than the melting temperature of the regenerated vinyl chloride resin, and the maximum expansion temperature is higher than the expansion start temperature. It is preferable to use capsules.
The melting temperature of the recycled vinyl chloride resin (the temperature at which the recycled vinyl chloride resin melts) is usually in the range of 130 ° C. to 150 ° C., although it depends on the type of waste material. It is preferable that the expansion start temperature and the maximum expansion temperature of the heat-expandable microcapsule outer shell are higher than the melting temperature of the regenerated vinyl chloride resin because it is not necessary to strictly control the temperature in the mixing step and the processability is excellent. .. Further, the temperature in the mixing step and the molding step cannot be raised to a temperature at which the recycled vinyl chloride resin is thermally deteriorated. Therefore, it is preferable that the expansion start temperature and the maximum expansion temperature of the heat-expandable microcapsule outer shell are set to be equal to or lower than the temperature at which the heat deteriorates.

For example, the expansion start temperature of the outer shell of the heat-expandable microcapsule is in the range of the melting temperature of the regenerated vinyl chloride resin of −10 ° C. and the melting temperature of the regenerated vinyl chloride resin of + 80 ° C., preferably regenerated. It is in the range of the melting temperature of the vinyl chloride resin to the melting temperature of the recycled vinyl chloride resin + 80 ° C., more preferably the melting temperature of the recycled vinyl chloride resin + 30 ° C. to the melting temperature of the recycled vinyl chloride resin + 80 ° C. be.
Further, for example, the maximum expansion temperature of the heat-expandable microcapsule outer shell is from the melting temperature of the regenerated vinyl chloride resin + 30 ° C. to the melting temperature of the regenerated vinyl chloride resin + 80 ° C., preferably the regenerated vinyl chloride resin. The melting temperature is + 50 ° C. to the melting temperature of the regenerated vinyl chloride resin + 80 ° C., and more preferably the melting temperature of the regenerated vinyl chloride resin is + 70 ° C. to the melting temperature of the regenerated vinyl chloride resin + 80 ° C. If a heat-expandable microcapsule having an excessively high maximum expansion temperature is used, the temperature at the time of molding must be raised in order to obtain sufficient thermal expansion, and the recycled vinyl chloride resin may be thermally deteriorated. Therefore, the maximum expansion temperature of the heat-expandable microcapsule outer shell is preferably in the above range.
Among the above, thermally expandable microcapsules having a small temperature difference between the expansion start temperature and the maximum expansion temperature are particularly preferable. For example, it is preferable to use heat-expandable microcapsules whose maximum expansion temperature is 5 ° C. to 15 ° C. higher than the expansion start temperature.
By using such heat-expandable microcapsules, it is possible to soften the outer shell while suppressing the expansion of the outer shell of the heat-expandable microcapsules in the material mixing step. By softening the outer shell, the expansion start temperature is lowered, and the heat-expandable microcapsules can be greatly expanded in the molding step described later, and a good foamed resin layer can be formed. The expansion start temperature and the maximum expansion temperature can be measured by the methods described in the following examples.
The melting temperature of the recycled vinyl chloride resin can be estimated from the composition of the waste material, or can be estimated from the sample obtained from the waste material. It can also be known by measuring the temperature at which the recycled vinyl chloride resin melts in the mixing step.

Specific examples of the heat-expandable microcapsules include low-boiling hydrocarbons such as n-butane, i-butane, pentane, and neopentane as inclusion components, and acrylic acid esters such as vinylidene chloride, acrylonitrile, and methyl methacrylate. , A thermoplastic resin containing an aromatic vinyl compound as a main component, such as styrene, as an outer shell.
For example, hydrocarbon-based inclusion components such as isobutane, isopentane, isohexane, and isooctane disclosed in WO99 / 43758 are encapsulated in an outer shell made of a polymer having a large gas barrier property such as a vinylidene chloride / acrylonitrile copolymer. It is preferable to use one.
Commercially available products can be used as the heat-expandable microcapsules. Commercial products include the product names "Matsumoto Microsphere F-80", "F-100", and "F-180" manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd., and the product name "Expansel WU-" manufactured by Nippon Phillite Co., Ltd. 461 ”,“ DU-950 ”,“ DU-098 ”, trade names“ Advancel EMH401 ”,“ EM403 ”,“ EM501 ”, etc. manufactured by Sekisui Chemical Co., Ltd. can be mentioned.
In particular, in the present invention for extrusion molding, it is preferable to use heat-expandable microcapsules having excellent heat resistance. Such heat-expandable microcapsules include heat-expandable microcapsules having an outer shell formed of a polymer composed of a nitrile-based monomer and a monomer having a carboxyl group, and further, a nitrile-based monomer disclosed in WO2004 / 058910. , A monomer having a carboxyl group, a monomer having an amide group, a heat-expandable microcapsule having an outer shell formed from a polymer composed of a monomer having a cyclic structure in a side chain, and the like.

The particle size of the heat-expandable microcapsules before foaming is not particularly limited, but for example, the volume average particle size is about 1 μm to 500 μm, preferably about 3 μm to 100 μm, and more preferably 5 μm to 50 μm. .. If the average particle size is too small, it is difficult to obtain a sufficiently foamed foamed resin layer, and if the average particle size is too large, the introduced cavity (cell diameter) becomes large and the strength of the foamed resin layer decreases. There is a risk. By using the heat-expandable microcapsules having the average particle size, a foamed resin layer having a relatively small cavity can be obtained. The foamed resin layer having a relatively small cavity has almost no variation between products, and stress is hard to concentrate when bent, so that it is hard to crack.
The volume average particle diameter is a value measured with a microscope measuring machine, specifically, a 3D digital fine scope "VC7700" manufactured by OMRON Corporation.

The specific gravity of the heat-expandable microcapsules is not particularly limited. In general, microcapsules with a low specific density tend to have a thin outer shell and a low compressive strength, so the outer shell tends to be easily destroyed by stress applied during extrusion molding. The light weight effect when the same amount is added is smaller than that of the one having a small specific gravity. From this point of view, the specific gravity of the heat-expandable microcapsules is preferably 0.2 to 1.2, preferably 0.4 to 1.2, in order to obtain a material having excellent lightweight effect and excellent molding processability by reducing the blending amount. 1.0 is more preferable.

The filler is not particularly limited, and an inorganic filler conventionally added to the vinyl chloride resin can be appropriately used. For example, calcium carbonate, calcium oxide, barium carbonate, magnesium hydroxide, aluminum hydroxide, etc. Examples include various inorganic fillers such as clay, talc and mica.
The plasticizer is not particularly limited, and those conventionally added to vinyl chloride resins can be appropriately used. For example, dioctyl phthalate (DOP), dibutyl phthalate (DBP), butyl octyl phthalate (BOP) can be used. And so on.
Examples of other additives include stabilizers, processing aids, fungicides, flame retardants, ultraviolet absorbers, colorants such as pigments, antioxidants, lubricants and the like.

The mixing gives a material for forming the foamed resin layer.
The amount of the recycled vinyl chloride resin in the material for forming the foamed resin layer is not particularly limited.
Further, by adding a virgin vinyl chloride resin, foaming can be performed more stably. When the virgin vinyl chloride resin is blended, the ratio of the recycled vinyl chloride resin to the virgin vinyl chloride resin is preferably recycled vinyl chloride: virgin vinyl chloride resin (mass ratio) = 8: 2 to 5: 5. However, according to the present invention, a good foamed resin layer can be formed only with the regenerated vinyl chloride resin without adding virgin.
The amount of the heat-expandable microcapsules is not particularly limited, but if it is too small, a well-foamed foamed resin layer may not be obtained, and if it is too large, the amount of other components is relatively small. From this point of view, when the total amount of the material for forming the foamed resin layer is 100% by mass, the amount of the heat-expandable microcapsules is preferably 0.1% by mass to 3% by mass, and further 0.2. More preferably, it is from% by mass to 2.5% by mass.

The amount of the plasticizer is not particularly limited, but if it is too small, the flexibility of the foamed resin layer may be insufficient, and if it is too large, the strength of the foamed resin layer may be insufficient. From this point of view, when the total amount of the material for forming the foamed resin layer is 100% by mass, the amount of the plasticizer is preferably 10% by mass to 30% by mass, and further, 15% by mass to 25% by mass. More preferably.
The amount of other additives such as stabilizers is not particularly limited, and is 0.5% by mass to 3% by mass when the total amount of the material for forming the foamed resin layer is 100% by mass.
The material for forming the foamed resin layer may or may not contain a filler. When the forming material contains a filler, the amount thereof is not particularly limited, but if it is too large, the foamed resin layer may be brittle and easily cracked. From this point of view, when the total amount of the material for forming the foamed resin layer is 100% by mass, the amount of the filler is preferably more than 0 and 70% by mass or less, and more than 0 and 68% by mass or less. Is more preferable.

The waste material mainly contains a recycled vinyl chloride resin, but in many cases, it also contains a filler, a plasticizer, and other additives. If the composition of the waste material is known in advance, it is taken into consideration, and if the composition of the waste material is not known, the composition of the waste material is known by sampling from the waste material and performing composition analysis. Can be done. The amount of the recycled vinyl chloride resin, the filler, the plasticizer, and other additives, which is the composition of the material for forming the foamed resin layer, is appropriately added in consideration of the composition of the waste material. It can be adjusted by. However, since other additives such as stabilizers contained in the waste material are often deteriorated, it is preferable to add the required amount of the other additives without considering the composition of the waste material. ..
Further, when the forming material contains a filler, the desired amount may not be obtained only with the filler contained in the waste material. In such a case, an appropriate amount of the filler is added.

The crushed waste material and unexpanded heat-expandable microcapsules, additional fillers, plasticizers and other additives as needed are placed in a mixing device and mixed.
The crushed waste material and the heat-expandable microcapsules, fillers, plasticizers and other additives added as needed may be added to the mixing device at the same time or sequentially.
When each material is mixed in sequence, for example,
(A) Except for the unexpanded heat-expandable microcapsules, the crushed waste material (recycled vinyl chloride resin), the plasticizer and other additives are mixed at the same time, and then the filler is added and further mixed. Add unexpanded thermally expandable microcapsules and mix to complete the mixing process,
(B) Except for the unexpanded heat-expandable microcapsules, the crushed waste material (recycled vinyl chloride resin), the plasticizer, the filler, and other additives are mixed at the same time, and then the unexpanded heat-expandable microcapsules are mixed. Add capsules and mix to complete the mixing process,
(C) Excluding the unexpanded heat-expandable microcapsules, the crushed waste material (recycled vinyl chloride resin) and the plasticizer are mixed at the same time, then other additives are added and mixed, and the filler is added. After further mixing, unexpanded thermoplastic microcapsules are added and mixed to complete the mixing step.
(D) Except for the unexpanded heat-expandable microcapsules, the crushed waste material (recycled vinyl chloride resin), the plasticizer and other additives are mixed at the same time, and then the unexpanded heat-expandable microcapsules are added. And mix to complete the mixing process.

When mixed as described above, the waste material melts and the material becomes a fluid gel as a whole. When no filler is added, the material is conveyed in this gel state and processed in the molding step described later.
On the other hand, when an filler is additionally blended, the material becomes powdery when the filler is added after the gel is formed and the mixing is continued. It is an unexpected result that when a filler is added to the regenerated vinyl chloride resin which has been melted into a gel, it changes into a powder. By powdering the material, it is easy to carry and mold.
Specifically, the waste material is mixed at a first temperature or a second temperature, which will be described later, to obtain a gel-like material, and then an inorganic filler is added. The planned mixing temperature after charging the filler is, for example, a first temperature of −10 ° C. to a first temperature of + 10 ° C. If the mixing is continued even after the filler is added, the gel-like material changes into a powder.
The timing of adding the heat-expandable microcapsules when adding the filler is also not particularly limited, and the heat-expandable microcapsules may be mixed with the waste material before the filler is added, or may be mixed with the filler. It may be added at the same time, or the filler may be added after the addition. Since the expansion prevention of the heat-expandable microcapsules and the heat-expandable microcapsules are uniformly dispersed in the material, it is preferable to mix the heat-expandable microcapsules after the material is changed into a powdery material.

The material mixing time, the rotation speed of the mixing device, and the like can be appropriately set in consideration of the total amount of materials and the like. The material may be mixed at the above heating temperature until the material becomes a gel, and then a filler is added to continue the mixing so that the mixing is stopped when the material becomes powdery.
After mixing, if necessary, in order to remove the rough heat, the mixed material is mixed while being cooled to 40 ° C. to 70 ° C. using, for example, a cooling mixer.
The obtained powdery forming material may be used as it is, but it is preferable to sift the powdery forming material in order to form a homogeneous foamed resin layer. For example, the powdery forming material is sifted through a 12 mesh sieve. The forming material that has passed through the sieve is a powdery body having a particle size of approximately 1.5 mm or less.

The mixing may be carried out at room temperature, but while the materials are being mixed, the materials themselves generate heat and the temperature rises. In the mixing step, it is preferable to control this temperature. That is, the target temperature range at the time of mixing is set in advance, the mixture is mixed until the temperature is reached, and the mixture is further maintained while maintaining the temperature range. Hereinafter, this target temperature may be referred to as a planned mixing temperature. If the temperature does not reach the planned mixing temperature during mixing, it is preferable to apply heat until the temperature is reached. Further, since the physical properties of the vinyl chloride resin contained in the waste material are not stable, it is preferable that the temperature at the time of mixing is constantly monitored by an operator or a mechanical sensor throughout the mixing operation.

The planned mixing temperature is set as appropriate. The planned mixing temperature may be lower than the melting temperature of the regenerated vinyl chloride resin, or may be higher than the melting temperature of the regenerated vinyl chloride resin. The planned mixing temperature is, for example, a temperature range equal to or higher than the melting temperature of the regenerated vinyl chloride resin, preferably higher than the melting temperature of the regenerated vinyl chloride resin and lower than the expansion start temperature of the thermally expandable microcapsules.
The planned mixing temperature may be one, but it is preferable to set a plurality of temperatures stepwise according to the progress of mixing. When there are a plurality of planned mixing temperatures, the respective temperatures are different. Hereinafter, when there are a plurality of planned mixing temperatures, the respective temperatures are distinguished as a first temperature, a second temperature, and a third temperature.

For example, the first temperature is from the melting temperature of the regenerated vinyl chloride resin to its melting temperature + 40 ° C, preferably from the melting temperature of the regenerated vinyl chloride resin + 10 ° C to its melting temperature + 30 ° C. If the temperature is lower than the melting temperature of the regenerated vinyl chloride resin, the regenerated vinyl chloride resin and the additives may not be sufficiently mixed, and if the regenerated vinyl chloride resin is mixed at an excessively high temperature, the regenerated vinyl chloride resin may be deteriorated. Specifically, the first temperature is 140 ° C. to 180 ° C., preferably 150 ° C. to 170 ° C. The melting temperature of the recycled vinyl chloride resin is usually in the range of 130 ° C. to 150 ° C., although it depends on the type of waste material. The melting temperature of the recycled vinyl chloride resin can be obtained by sampling from the waste material as described above.

The second temperature is, for example, in the range of the melting temperature of the regenerated vinyl chloride resin or higher and lower than the expansion starting temperature of the heat-expandable microcapsules. By mixing at such a temperature, the filler or the like can be sufficiently mixed with the regenerated vinyl chloride resin, and most of the heat-expandable microcapsules do not expand significantly in the mixing process, and the heat-expandable microcapsules do not expand significantly in the subsequent molding process. It is possible to prevent the capsule from being destroyed. For example, the second temperature is the melting temperature of the recycled vinyl chloride resin + 10 ° C. to the expansion start temperature of the thermally expandable microcapsules −10 ° C., and specifically, the second temperature is 150 ° C. to 175 ° C. ..

Further, the third temperature is lower than the melting temperature of the regenerated vinyl chloride resin, preferably the melting temperature of the regenerated vinyl chloride resin of −70 ° C. to the melting temperature of −20 ° C., and more preferably the regenerated vinyl chloride. The melting temperature of the based resin is −60 ° C. to the melting temperature of −30 ° C. By mixing at such a temperature, most of the heat-expandable microcapsules do not expand significantly in the mixing step, and it is possible to prevent the heat-expandable microcapsules from being destroyed in the subsequent molding step. Specifically, the third temperature is 60 ° C. to 130 ° C., preferably 90 ° C. to 110 ° C.
The first temperature and the second temperature have overlapping ranges, but the actual mixing temperatures are different from each other. That is, the first temperature, the second temperature, and the third temperature are not the same temperature but different. For example, it is preferable that the relationship of second temperature> first temperature> third temperature is satisfied.

In the mixing step, when the planned mixing temperature is one (one target temperature), the temperature is preferably the first temperature or the second temperature. When the planned mixing temperature is one, the crushed waste material containing the recycled vinyl chloride resin and the heat-expandable microcapsules, and the fillers, plasticizers and other additives added as needed are simultaneously put into the mixing device. Mix them until they reach at least the expected mixing temperature. Alternatively, when the planned mixing temperature is one, a pulverized waste material containing a recycled vinyl chloride resin, a heat-expandable microcapsule, a filler added as necessary, a plasticizer, and other additives are sequentially mixed. And mix until they reach at least the expected mixing temperature.

Further, when a plurality of planned mixing temperatures are set in the mixing step, it is preferable to set at least two temperature ranges selected from the first temperature to the third temperature stepwise. When there are a plurality of planned mixing temperatures, all the materials such as crushed waste materials containing recycled vinyl chloride resin may be put into the mixing device at the same time and mixed, but since each material can be mixed well, they are mixed sequentially. It is preferable to continue.

-First mixing example In the first mixing example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives were put into the mixing device at the same time and mixed so that the planned mixing temperature became the first temperature. After that, a filler is added to the material and the mixture is continuously mixed until the first temperature is reached, and then unexpanded heat-expandable microcapsules are added to the material and the mixture is continued at the first temperature.
For example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives are put into a mixing device at the same time and mixed for about 10 to 40 minutes to set the material temperature to the first temperature (140 ° C to 180 ° C). The mixing step is completed by adding a filler and mixing until the temperature reaches the first temperature again, and further adding unexpanded heat-expandable microcapsules and continuing to mix at the first temperature.

-Second Mixing Example In the second mixing example, the crushed waste material containing the recycled vinyl chloride resin, the plasticizer and other additives were put into the mixing device at the same time and mixed so that the planned mixing temperature became the second temperature. After that, a filler is added to the material and mixed again until the temperature reaches the second temperature, and then unexpanded heat-expandable microcapsules are added to the material and continuously mixed at the second temperature.
For example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives are put into a mixing device at the same time and mixed for about 10 to 40 minutes to set the material temperature to the second temperature (150 ° C to 175 ° C). The mixing step is completed by adding a filler and mixing until the temperature reaches the second temperature again, and further adding unexpanded heat-expandable microcapsules and continuing to mix at the second temperature.

-Third Mixing Example In the third mixing example, the crushed waste material containing the recycled vinyl chloride resin, the plasticizer and other additives were put into the mixing device at the same time and mixed so that the planned mixing temperature became the first temperature. After that, a filler is added to the material and mixed to a second temperature, and then unexpanded heat-expandable microcapsules are added to the material and continuously mixed at the second temperature.
For example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives are put into a mixing device at the same time and mixed for about 10 to 40 minutes to set the material temperature to the first temperature (140 ° C to 170 ° C). The mixing step is carried out by adding a filler and mixing until the temperature reaches a second temperature (150 ° C. to 175 ° C.), then adding an unexpanded heat-expandable microcapsule and continuing to mix at the second temperature. finish.

-Fourth Mixing Example In the fourth mixing example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives were put into the mixing device at the same time and mixed so that the planned mixing temperature became the first temperature. After that, a filler is added to the material and mixed to reach the second temperature, then the temperature is lowered to the third temperature, and unexpanded thermally expandable microcapsules are added to the lowered material to continue at the third temperature. Mix.
For example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives are put into a mixing device at the same time and mixed for about 10 to 40 minutes to set the material temperature to the first temperature (140 ° C to 170 ° C). After that, a filler was added and mixed until the temperature reached the second temperature (150 ° C to 175 ° C), and then cooled to the third temperature (60 ° C to 130 ° C) over about 5 to 15 minutes. After that, the mixing step is completed by adding unexpanded heat-expandable microcapsules and continuing to mix at the third temperature.

-Fifth Mixing Example In the fifth mixing example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives were put into the mixing device at the same time and mixed so that the planned mixing temperature became the first temperature. After that, a filler is added to the material and mixed again until the first temperature is reached, then the temperature is lowered to the third temperature, and unexpanded thermally expandable microcapsules are added to the lowered material and continued at the third temperature. Mix.
For example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives are put into a mixing device at the same time and mixed for about 10 to 40 minutes to set the material temperature to the first temperature (140 ° C to 170 ° C). After adding the filler and mixing until the first temperature is reached again, it takes about 5 to 15 minutes to cool to the third temperature (60 ° C to 130 ° C), and then the unexpanded heat. The mixing step is completed by placing inflatable microcapsules and continuing to mix at a third temperature.

-Sixth Mixing Example In the sixth mixing example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives were put into the mixing device at the same time and mixed so that the planned mixing temperature became the second temperature. After that, a filler is added to the material and mixed again until the temperature reaches the second temperature, then the temperature is lowered to the third temperature, and the unexpanded heat-expandable microcapsules are put into the material whose temperature has been lowered, and the temperature is continued at the third temperature. Mix.
For example, crushed waste material containing recycled vinyl chloride resin, plasticizer and other additives are put into a mixing device at the same time and mixed for about 10 to 40 minutes to set the material temperature to the second temperature (150 ° C to 175 ° C). After adding the filler and mixing again until the temperature reaches the second temperature, it takes about 5 to 15 minutes to cool to the third temperature (60 ° C. to 130 ° C.), and then the unexpanded heat. The mixing step is completed by placing inflatable microcapsules and continuing to mix at a third temperature.

As in the 4th mixing example to the 6th mixing example, the expansion of the heat-expandable microcapsules is expanded by lowering the temperature lower than the melting temperature of the regenerated vinyl chloride resin before inserting the heat-expandable microcapsules. Can be prevented. Destruction of the heat-expandable microcapsules is caused by preventing the unexpanded heat-expandable microcapsules from being exposed to a temperature higher than the third temperature in the mixing step as in the fourth mixing example to the sixth mixing example. It can be suppressed, and as a result, the expansion ratio in the molding process can be increased. Further, since the heat-expandable microcapsules are not exposed to a temperature higher than the third temperature in the mixing step, the heat-expandable microcapsules having a relatively low expansion start temperature of the outer shell can also be used, and the heat-expandable microcapsules can be used. Increased freedom in capsule selection and design.
The cooling before inserting the heat-expandable microcapsules may be natural cooling, but it is preferable to forcibly lower the temperature by using a cooling device. For example, in the 4th to 6th mixing examples, the filler is added and mixed with a super mixer, and then the material mixed up to the filler is transferred to a cooling mixer, lowered to a third temperature, and then the temperature is lowered. Add unexpanded heat-expandable microcapsules and continue mixing with the cooling mixer.
When the first temperature and the second temperature coexist as in the third mixing example and the fourth mixing example, the second temperature is preferably higher than the first temperature. By applying a certain amount of heat to the material to be mixed, gelation of the material is likely to be promoted in the subsequent molding step, and workability is improved.

(Molding process)
The molding step is a step of extruding the material obtained in the mixing step while heating to form a foamed resin layer.
When the forming material obtained in the mixing step is gel-like, the gel-like material is extruded, and when the forming material obtained in the mixing step is powder-like, the powder-like material is extruded. Put it in the hopper of the machine. As the extrusion molding machine, a conventionally known one may be used.
The processing temperature at the time of extrusion is equal to or higher than the melting temperature of the regenerated vinyl chloride resin, and is preferably in the temperature range of the melting temperature of the regenerated vinyl chloride resin to the maximum expansion temperature of the thermally expandable microcapsules + 10 ° C. For example, it is 150 ° C. to 200 ° C., preferably 160 ° C. to 200 ° C. The processing temperature at the time of molding is preferably higher than the planned mixing temperature.
By extruding the heated material from the die of the extrusion molding machine into a sheet shape, a long strip-shaped foamed resin layer having a predetermined width is formed.

Since the outer shell of the heat-expandable microcapsules is softened during the mixing step as described above, the expansion start temperature of the heat-expandable microcapsules after the mixing step is lower than that before the mixing step. When the processing temperature of the molding process is equal to or higher than the maximum expansion temperature of the heat-expandable microcapsules, it can be sufficiently expanded, and even if it is lower than the maximum expansion temperature of the heat-expandable microcapsules, it is thermally expandable. The microcapsules can be fully inflated. Specifically, in general, even if molded at a temperature equal to or higher than the maximum expansion temperature of the heat-expandable microcapsules, some of the microcapsules do not expand sufficiently. In this regard, by mixing the materials as described above, the expansion start temperature of the heat-expandable microcapsules after the mixing step is lower than the design expansion start temperature. Therefore, even if the temperature is lower than the maximum expansion temperature of the microcapsules, and further, if the temperature is equal to or higher than the maximum expansion temperature, the heat-expandable microcapsules can be sufficiently expanded, and a foamed resin layer can be formed satisfactorily.
Therefore, even if the processing temperature at the time of molding is not strictly controlled, it is possible to form a foamed resin layer having a relatively large cavity and foamed substantially uniformly.
The thickness of the foamed resin layer is not particularly limited and can be appropriately set. The thickness of the foamed resin layer is not particularly limited, but is, for example, 0.5 mm to 5 mm, preferably 1 mm to 3 mm. If the thickness of the foamed resin layer is too small, the cushioning property of the floor material is poor, and if it is too large, the sole of the foot in contact with the floor material may sink too much.
The foaming ratio of the foamed resin layer is also not particularly limited, and is, for example, 1.05 to 2 times in terms of specific gravity. If the foaming ratio is too small, the cushioning property of the floor material is poor, and if it is too large, the floor material tends to be worn out.

<Preparation process for each layer other than the foamed resin layer>
Separately, a protective layer, a decorative layer, a resin layer, a first base material layer and a second base material layer are prepared. These layers are in the shape of a long strip having a predetermined width, and preferably, a long strip having a width substantially the same as that of the foamed resin layer is prepared. When a resin layer having a design property is used, the decorative layer is omitted.
The method for forming the protective layer and the resin layer is not particularly limited, and can be appropriately selected depending on the material for forming them. Examples thereof include a calendar method, an extrusion molding method, and a solution casting method.
Further, the protective layer, the decorative layer, the resin layer, the first base material layer and the second base material layer may be independent of each other, or even in a state where any two or more layers selected from these are integrally laminated. good.

<Laminating process>
As shown in FIG. 8, the first base material layer 61, the resin layer 5, the decorative layer 4 and the protective layer 3 are laminated on the upper surface of the foamed resin layer 7, and the second base material layer is laminated on the lower surface of the foamed resin layer 7. Each layer is integrated by laminating 62 and passing it between a pair of rolls 81 and 82 to heat and pressurize.
Specifically, a pair of heating rolls are formed by stacking a laminated body in which a protective layer 3, a decorative layer 4, a resin layer 5, a first base material layer 61, a foamed resin layer 7 and a second base material layer 62 are overlapped in this order from the upper side. By passing it between 81 and 82 (or the heating roll 81 and the resin roll 82), the laminate is heated and pressed, and the layers are joined.
As described above, for example, when an arbitrary two or more layers are prepared in the preparation step, the two or more layers are used in FIG. 8.

Examples of the method of joining each layer by heating and pressurizing include a laminating method, a calendar forming method, and a continuous pressing method. Above all, a method of continuously joining laminated bodies by heating and pressing with a roll, such as a laminating method and a calendar forming method, is preferable because many products can be manufactured at one time. In particular, the laminating method can be most preferably applied in the present invention because many laminated bodies can be joined at one time. The heating temperature and pressure of the laminating method are appropriately set according to a known processing method. For example, the heating temperature of the laminate is 140 ° C. to 200 DEG ° C., the pressure between the rolls ^{is 20kgf / cm 2 ~100kgf / cm 2} .
The flooring material shown in the second to fifth embodiments can be obtained by omitting an appropriate layer from each of the layers shown in FIG. 8 or adding an appropriate layer.

<Embossing process>
The embossing step is performed as necessary to form irregularities on the upper surface or the lower surface of the laminated body 11. By passing between the rolls 81 and 82 and passing the laminated body 11 in which each layer is integrated between the embossed roll 83 and the receiving roll 84, unevenness is formed on the laminated body 11.

<Formation process of scratch prevention layer>
This step is performed as necessary to form the scratch prevention layer 2 on the upper surface of the protective layer 3.
The upper surface of the laminate 11 is coated with, for example, an ionizing radiation curable monomer or an oligomer (material for forming the scratch prevention layer 2) using a roll coater 85 or the like, and ionizing using an ionizing radiation irradiation device 86. By irradiating with radiation, a floor material having a scratch prevention layer 2 formed on the uppermost surface can be obtained.
The obtained long strip-shaped flooring material 1 is wound up on a roll as needed and used for storage and transportation. When the flooring material of the present invention is a single-wafered tile, the long strip-shaped flooring material is cut into an appropriate size by punching, cutting, etc., and then stored and transported in layers. It is offered to.

Since the flooring material of the present invention is formed by using a recycled vinyl chloride resin, it is environmentally preferable.
According to the production method of the present invention, the recycled vinyl chloride resin can be foamed substantially uniformly, and a flooring material having sufficient strength and appropriate flexibility can be obtained.
Further, according to the production method of the present invention, since it has a good foamed resin layer, it is possible to obtain a flooring material which is lightened as a whole.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to the following examples.

[Material used]
-Protective layer Product name "Clear Film" manufactured by Hiroshima Kasei Co., Ltd. Thickness 0.37 mm.
-Cosmetic layer printing paper. Product name "Center Film" manufactured by Hiroshima Kasei Co., Ltd. Thickness 0.15 mm.
-Resin layer paste Vinyl chloride resin. Product name "Kaneka" made by Kaneka Corporation. Degree of polymerization: 1150, K value: 69.
-Base layer glass non-woven fabric. Product name "Gravest" manufactured by Oribest Co., Ltd. Thickness of glass fiber: diameter about 18 μm, length of glass fiber: about 13 mm, grain amount of glass fiber: 37 g / m ² .
-Waste materials Used agricultural vinyl chloride resin sheets and vinyl chloride flooring scraps.
The composition of the used agricultural vinyl chloride resin sheet among the waste materials is known in advance, and is composed of 70% by mass of the vinyl chloride resin and 30% by mass of the plasticizer dioctyl phthalate. The composition of the scraps of the vinyl chloride flooring material is also known in advance, and is composed of 24% by mass of vinyl chloride resin, 15% by mass of dioctyl phthalate as a plasticizer, and 61% by mass of calcium carbonate as a filler. .. The melting temperature of the vinyl chloride resin contained in the waste material was 140 ° C.
-Virgin vinyl chloride resin Product name "ZEST1000" manufactured by Shin Daiichi PVC Co., Ltd. Degree of polymerization 1050.
-Heat-expandable microcapsules Matsumoto Yushi Pharmaceutical Co., Ltd.'s brand name "Matsumoto Microsphere Unexpanded Grade F, FN Series". The expansion start temperature of the microcapsules was 185 ° C, and the maximum expansion temperature was 190 ° C.
・ Filler Calcium carbonate. Product name "S Light" manufactured by Nitto Flour Chemical Co., Ltd.
-Plasticizer Dioctyl phthalate. Product name "Sun Sizar" manufactured by Shin Nihon Rika Co., Ltd.
-Stabilizer Product name "Grec MP550" manufactured by Nittatsu Trading Co., Ltd.
-Processing aid Sanyo Kasei Co., Ltd.'s product name "Viscol 550P".

[Measurement of expansion start temperature (Ts) and maximum expansion temperature (Tmax)]
The expansion start temperature and the maximum expansion temperature were measured as follows.
As a measuring device, DMA (DMA Q800 type, manufactured by TA instruments) was used. Place 0.5 mg of microcapsules in an aluminum cup with a diameter of 6.0 mm (inner diameter 5.65 mm) and a depth of 4.8 mm, and place an aluminum lid (diameter 5.6 mm, 0.1 mm) on the top of the microsphere layer. Prepared the sample. The height of the sample was measured with a force of 0.01 N applied to the sample from above with a pressurizer. With a force of 0.01 N applied by the pressurizer, the pressurizer was heated from 20 ° C. to 300 ° C. at a heating rate of 10 ° C./min, and the amount of displacement of the pressurizer in the vertical direction was measured. The displacement start temperature in the positive direction was defined as the expansion start temperature (Ts), and the temperature when the maximum displacement amount was indicated was measured as the maximum expansion temperature (Tmax).

Table 1 shows the blending amount of each material in the material mixing step of each example. Table 2 shows the blending amount of each material in the material mixing step of each comparative example. The unit of numerical values in Tables 1 and 2 is kg (kilogram-force).

[Example 1]
<Mixing process>
The waste material was crushed using a crusher and sieved with an 8-mesh mesh to obtain a crushed product of the waste material.
The crushed product of the waste material, the plasticizer, the stabilizer, and the processing aid are put into a super mixer (trade name "SMG-500" manufactured by Kawata Co., Ltd.) at the ratio shown in Table 1 and stirred. After kneading for about 15 minutes at a blade rotation speed of 1000 rpm, the entire material became a gel, and immediately after that, the above filler was added. This filler is not contained in the waste material, but is virgin (trade name "S light" manufactured by Nitto Flour Chemical Co., Ltd.). The amount of filler added is shown in Table 1. The material temperature for about 15 minutes was about 160 ° C.
After adding the filler, the material was similarly kneaded for about 10 minutes at the same rotation speed of the stirring blade while appropriately measuring the material temperature, and the whole material changed to powder. The material temperature for about 10 minutes decreased once immediately after the filler was added, but increased by kneading, and finally reached about 160 ° C. Immediately after the material changed to powder, the unexpanded heat-expandable microcapsules were added, kneaded at about 160 ° C. for about 1 minute, and then the mixer was stopped. The amount of the heat-expandable microcapsules is shown in Table 1.
Next, this was stirred while cooling, and the rough heat was removed to bring it to 60 ° C. The obtained powdery material was sieved with a mesh of 12 meshes, and the material that passed through the sieve was used as a material for forming the foamed resin layer.

<Molding process and laminating process>
The material for forming the foamed resin layer was put into a hopper of an extrusion molding machine and extruded at a temperature of 180 ° C. to form a foamed resin layer having a thickness of 1.8 mm, a width of 1950 mm, and a length of 10 m.
The base material layer is superposed on the upper surface of the foamed resin layer, and a paste vinyl chloride resin is coated on the base material layer to form a resin layer having a thickness of about 0.3 mm, and further, the decorative layer and the protective layer are formed on the resin layer. A laminate was formed by stacking the layers.
In a state where this laminate is heated to 150 ° C. with a preheater, the laminate is passed between the upper and lower laminate rolls at 50 ° C. to form a long strip having a thickness of about 2.5 mm, a width of 1950 mm, and a length of 10 m. A flooring material was prepared. The transport speed of the laminated body was about 10 m / min, and the pressure applied to the laminated body was 40 kgf / cm ² .

[Examples 2 to 13]
A flooring material was produced in the same manner as in Example 1 except that the blending amount of each material was changed as shown in Table 1. However, in Example 13, the amount of the virgin vinyl chloride resin shown in Table 1 was put into the mixer at the same time as the pulverized product.

[Comparative Examples 1 to 3]
A flooring material was prepared in the same manner as in Example 1 except that the heat-expandable microcapsules were not added in the mixing step and the blending amounts of each material were set as shown in Table 2.

[Comparative Example 4]
In the heat mixing step, a chemical foaming agent (trade name "Vinihole AC # 3" manufactured by Eiwa Kasei Kogyo Co., Ltd.) was used instead of the expandable microcapsules, and each material was mixed with the amount shown in Table 2. A flooring material was produced in the same manner as in Example 1 except for the above. However, in Comparative Example 4, the amount of the virgin vinyl chloride resin shown in Table 2 was put into the mixer at the same time as the pulverized product.

[Comparative Example 5]
In the mixing step, hollow particles (VS light. Trade name "DA20-N" manufactured by Sankyo Flour Milling Co., Ltd., peak particle size: 48 μm) were used instead of the heat-expandable microcapsules, and each material is shown in the table. A floor material was produced in the same manner as in Example 1 except that the blending amount shown in 2 was used.

[Comparative Example 6]
In the mixing step, instead of the unexpanded heat-expandable microcapsules, hollow particles (pre-expanded microcapsules. The trade name "Matsumoto Microsphere F-65DE" manufactured by Matsumoto Yushi Pharmaceutical Co., Ltd. was heated to maximize expansion. The floor material was prepared in the same manner as in Example 1 except that the material was used and the blending amount of each material was as shown in Table 2.

[Comparative Example 7]
In the mixing process, styrofoam granules (trade name "HEATMAX HM5" manufactured by Kaneka Corporation. Particle size: 3 mm) were used instead of the heat-expandable microcapsules, and each material is shown in Table 2. A floor material was produced in the same manner as in Example 1 except that the blending amount was as shown.

The compositions of Tables 3 and 4 are obtained by reconverting the materials for forming the foamed resin layer obtained in the mixing steps of the Examples and Comparative Examples for each component. The numerical values of the compositions in Tables 3 and 4 are expressed in% by mass.
Specifically, as described above, the used agricultural vinyl chloride resin sheet is made of vinyl chloride resin: plasticizer = 70:30 (mass ratio), and the scraps of the vinyl chloride flooring material are vinyl chloride. The system resin: plasticizer: filler = 24:15:61 (mass ratio). For example, in Example 1, since the used product is blended in an amount of 159 parts by mass, it is required from this product that the recycled vinyl chloride resin is 159 × 70/100 = 111.3. Since it is partially blended, it is required that the recycled vinyl chloride resin is 55 × 24/100 = 13.2 from this offcut. From the total amount of these recycled vinyl chloride resins and the total amount of forming materials, as shown in Table 3, the ratio of the recycled vinyl chloride resin to the entire forming material is (111.3 + 13.2) /331.1=. It will be 37.6%. The filler and the like can be obtained in the same manner. The plasticizer and filler are the total of the one contained in the waste material and the newly added virgin, respectively.

[State when mixed]
For each Example and Comparative Example, the state when each material was mixed was observed. As in the examples, when the materials were mixed to some extent and then the filler was added, the powder changed into a powder, and the state of the powder was evaluated.
The criteria for evaluation are ○ when a powdery body with a particle size of about 1.5 mm or less is obtained that passes through a 12-mesh sieve, Δ when it is easy to produce something that does not pass through the sieve, and when it does not become powdery. It was evaluated as x. The results are shown in Tables 3 and 4.

[Workability during molding]
For each Example and Comparative Example, when molding the foamed resin layer, the ease of molding into a sheet was evaluated.
The criteria for evaluation of workability were evaluated as ◯ when it could be formed into a sheet, and × when it could not be formed into a sheet. The results are shown in Tables 3 and 4.
In Comparative Example 4, a foamed resin layer having a sufficient cavity could not be obtained.

[Weight measurement]
^{The weight (kg / m 2} ) of 1 square meter of the foamed resin layer obtained in each Example and Comparative Example was measured, and the weight of the foamed resin layer was evaluated.
The criteria for weight evaluation ^{are ◎ when it is 3.1 kg / m 2} or less, ○ when it is more than 3.1 and 3.3 or less, and △ 3 when it is more than 3.3 and 3.4 or less. When it exceeds 4 kg / m ² or less, it is marked with x. The results are shown in Tables 3 and 4.

[Effervescence magnification]
The foaming ratio of the foamed resin layer obtained in each Example and Comparative Example was calculated in terms of specific gravity.
Foaming magnification by specific gravity conversion = Specific gravity of the foamed resin layer formed into a sheet by crushing the cavity ÷ Specific gravity of the foamed resin layer.
The criteria for foaming evaluation were ◯ when it was 1.05 times or more, and × when it was less than 1.05 times. The results are shown in Tables 3 and 4.
The specific gravity was measured in accordance with the method for measuring density and specific gravity by the in-liquid weighing method of JIS Z 8807, and was measured using an electronic gravity meter manufactured by Alpha Mirage (trade name "ELECTRONIC DENSIMTER"). ..
As a method of crushing the cavity to form a sheet of the foamed resin layer, a method of kneading the foamed resin layer with a roll while heating it at a melting temperature or higher is adopted, and by this method, the foamed resin layer is made into a resin sheet without a cavity. Reformed.

[Bending crack test]
A bending crack test was conducted to confirm the flexibility and strength of the foamed resin layer obtained in each Example and Comparative Example.
In the bending crack test, the foamed resin layer is cut into a length x width = 5 cm x 30 cm to obtain a sample, and the sample is wound around a cylinder having a diameter of 6 mm and a cylinder having a diameter of 4 mm in an environment of 5 ° C., and the sample is cracked. I checked if it was. The results are shown in Tables 3 and 4.
In the test results, ○ indicates that the product did not crack even when wound around all the cylinders, and △ indicates that cracking occurred when the cylinder was wound with a diameter of 4 mm, but no crack occurred when the cylinder was wound with a diameter of 6 mm. X indicates that a crack occurred when the cylinder was wound around a cylinder having a diameter of 6 mm.
In Comparative Example 4, since the foamed resin layer could not be molded, the weight measurement, the expansion ratio, and the bending crack test were not performed.

A good foamed resin layer could be formed by extruding a regenerated vinyl chloride resin using unexpanded heat-expandable microcapsules as in Examples 1 to 13. It can be seen that the regenerated vinyl chloride resin cannot be foamed in Comparative Examples 1 to 7 in which the unexpanded heat-expandable microcapsules are not used as in Comparative Examples 1 to 7. Further, it can be seen that the flooring materials of Examples 1 to 13 can be easily bent and are not easily cracked when bent.

[Example 14]
<Mixing process>
The waste material was crushed using a crusher and sieved with an 8-mesh mesh to obtain a crushed product of the waste material.
In the ratio shown in Example 6 of Table 1, the crushed product of the waste material, the plasticizer, the stabilizer, and the processing aid were added to a super mixer (trade name "SMG-500" manufactured by Kawata Co., Ltd.). When the material is charged and kneaded at a stirring blade rotation speed of 1000 rpm for about 13 minutes, the entire material becomes a gel, and immediately after that, the same amount of the above filler as in Example 6 (trade name "S" manufactured by Nitto Flour Chemical Co., Ltd.) Light ") was added. The material temperature for about 13 minutes was about 150 ° C.
After adding the filler, the material was similarly kneaded for about 14 minutes at the same rotation speed of the stirring blade while appropriately measuring the material temperature, and the whole material changed to powder. The material temperature for about 14 minutes decreased once immediately after the filler was added, but increased by kneading, and finally reached about 160 ° C. Immediately after the material changed to powder, the same amount of unexpanded heat-expandable microcapsules as in Example 6 was added, kneaded for about 1 minute, and then the mixer was stopped.
Next, this was stirred while cooling, and the rough heat was removed to bring it to 60 ° C. The obtained powdery material was sieved with a mesh of 12 meshes, and the material that passed through the sieve was used as a material for forming the foamed resin layer.
Using this forming material, a foamed resin layer was formed in the same manner as in the <molding step and laminating step> of Example 1.

[Example 15]
<Mixing process>
The waste material was crushed using a crusher and sieved with an 8-mesh mesh to obtain a crushed product of the waste material.
In the ratio shown in Example 6 of Table 1, the crushed product of the waste material, the plasticizer, the stabilizer, and the processing aid were added to a super mixer (trade name "SMG-500" manufactured by Kawata Co., Ltd.). When the material is charged and kneaded at a stirring blade rotation speed of 1000 rpm for about 15 minutes, the entire material becomes a gel, and immediately after that, the same amount of the above filler as in Example 6 (trade name "S" manufactured by Nitto Flour Chemical Co., Ltd.) Light ") was added. The material temperature for about 15 minutes was about 160 ° C.
After adding the filler, similarly, while appropriately measuring the material temperature, kneading for about 10 minutes at the same rotation speed of the stirring blade causes the entire material to change into a powder, and immediately after the change, the mixer is turned on. It stopped. The material temperature for about 10 minutes decreased once immediately after the filler was added, but increased by kneading, and finally reached about 160 ° C.
Next, this is stirred while cooling, the rough heat is removed, the material temperature is lowered to 100 ° C., and then the same amount of the unexpanded heat-expandable microcapsules as in Example 6 is charged, and the temperature is approximately 100 ° C. After kneading for about 5 minutes, the mixer was stopped. The obtained powdery material was sieved with a mesh of 12 meshes, and the material that passed through the sieve was used as a material for forming the foamed resin layer.
Using this forming material, a foamed resin layer was formed in the same manner as in the <molding step and laminating step> of Example 1.

[Example 16]
<Mixing process>
The waste material was crushed using a crusher and sieved with an 8-mesh mesh to obtain a crushed product of the waste material.
In the ratio shown in Example 6 of Table 1, the crushed product of the waste material, the plasticizer, the stabilizer, and the processing aid were added to a super mixer (trade name "SMG-500" manufactured by Kawata Co., Ltd.). When the material is charged and kneaded at a stirring blade rotation speed of 1000 rpm for about 13 minutes, the entire material becomes a gel, and immediately after that, the same amount of the above filler as in Example 6 (trade name "S" manufactured by Nitto Flour Chemical Co., Ltd.) Light ") was added. The material temperature for about 13 minutes was about 150 ° C.
After adding the filler, similarly, while appropriately measuring the material temperature, kneading for about 14 minutes with the rotation speed of the stirring blade kept the same, the whole material changed to powder, and immediately after the change, the mixer was turned on. It stopped. The material temperature for about 14 minutes decreased once immediately after the filler was added, but increased by kneading, and finally reached about 160 ° C.
Next, this is stirred while cooling, the rough heat is removed, the material temperature is lowered to 100 ° C., and then the same amount of the unexpanded heat-expandable microcapsules as in Example 6 is charged, and the temperature is approximately 100 ° C. After kneading for about 5 minutes, the mixer was stopped. The obtained powdery material was sieved with a mesh of 12 meshes, and the material that passed through the sieve was used as a material for forming the foamed resin layer.
Using this forming material, a foamed resin layer was formed in the same manner as in the <molding step and laminating step> of Example 1.

[Measurement of specific gravity]
The specific densities of the foamed resin layers of Examples 6 and 14 to 16 were measured. The method for measuring the specific gravity of the foamed resin layer was the method described in the above [Expansion Magnification].
As a result, the specific density of Example 6 was 1.38, the specific density of Example 14 was 1.38, the specific density of Example 15 was 1.30, and the specific density of Example 16 was 1.31.
From this result, it can be seen that the foaming ratios of the foamed resin layers of Examples 15 and 16 are superior to those of Examples 6 and 14.
Examples 15 and 16 differ from Examples 6 and 14 in that the temperature of the material is lowered before adding the heat-expandable microcapsules in the material mixing step. It is presumed that the difference in the foaming ratio is due to the difference in the mixing process. It is considered that this is because if unexpanded heat-expandable microcapsules are added in a state where the material temperature is relatively high, the heat-expandable microcapsules cause foaming loss and the foaming efficiency deteriorates. According to the mixing method (material preparation method) in which the material temperature is lowered and then the heat-expandable microcapsules are added as in Examples 15 and 16, the outer shell has a relatively low expansion start temperature. Microcapsules can also be used, and it can be said that the degree of freedom in selection and design of thermally expandable microcapsules is increased.

1 Floor material 7 Foamed resin layer 7a Cavity 72 Outer shell of heat-expandable microcapsules

Claims (3)

The regenerated vinyl chloride resin is heated and melted to form a fluid gel, and by mixing it with calcium carbonate, which is a filler, the regenerated vinyl chloride resin and the filling are changed from a fluid gel to a powder. A mixing step of obtaining an intermediate material containing an agent, and then adding unexpanded heat-expandable microcapsules to the powdery intermediate material and mixing them to obtain a molding material.
A molding process in which the molding material is extruded while being heated to form a foamed resin layer.
A method for manufacturing a flooring material having. In the mixing step, the intermediate material and the unexpanded heat-expandable microcapsule material are mixed so that the temperature range is equal to or higher than the melting temperature of the regenerated vinyl chloride resin and lower than the expansion start temperature of the heat-expandable microcapsules. death,
The method for producing a flooring material according to claim 1, wherein in the molding step, heating is performed at a temperature equal to or higher than the melting temperature of the recycled vinyl chloride resin. In the mixing step, the material containing the regenerated vinyl chloride resin and the filler was mixed so as to be in a temperature range equal to or higher than the melting temperature of the regenerated vinyl chloride resin and lower than the expansion start temperature of the heat-expandable microcapsules. After that, the temperature is lowered to a temperature lower than the melting temperature of the regenerated vinyl chloride resin, and the unexpanded heat-expandable microcapsules are added to the intermediate material after the temperature is lowered and mixed again. Obtained molding material
The method for producing a flooring material according to claim 1, wherein in the molding step, heating is performed at a temperature equal to or higher than the melting temperature of the recycled vinyl chloride resin.

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