KR20210067033A - Floor sheet and method for manufacturing the same - Google Patents

Abstract

The present invention relates to a flooring material, comprising a foam layer; a printed layer formed on the foam layer; and a transparent layer formed on the printed layer, wherein a residual indentation ratio is less than 10%, a restoring force and appearance characteristics are excellent, and the foamed layer manufactured by extrusion foaming is applied.

Description

FLOOR SHEET AND METHOD FOR MANUFACTURING THE SAME

The present invention relates to a flooring material and a method for manufacturing the same.

The flooring material used in a building is manufactured to include a foam layer, which is a foam that gives a certain level of cushioning properties so that it can have a comfort and sound insulation effect. Such a foam is generally prepared by adding a foaming agent to a polyvinyl chloride resin, and a chemical foaming agent, which is one of the foaming agents, is decomposed and foamed by heat to form open cells in the foam.

However, since the open cell formed of the chemical foaming agent is easily deformed and broken by external pressure, the foam including the open cell has a problem of low stability. This problem caused the deformation and breakage of the open cells in the foam when continuous pressure was applied to the foam, thereby lowering the cushioning properties of the entire flooring material, thereby causing a problem in which the comfort and sound insulation effect of the flooring material were deteriorated.

In order to improve this problem, Korean Patent Laid-Open No. 10-2007-0059811 tried to prevent the formation of open cells by using a microcapsule foaming agent containing low-boiling hydrocarbons inside the cells of the thermoplastic nitrile-based copolymer, but in this case There was a problem in that cushioning properties and sound insulation properties were lowered.

In addition, in the conventional flooring manufacturing process using the calendering process, the transparent layer, the printed layer, and the foaming layer must be separately prepared in the form of a sheet, and the manufacturing process is complicated because it is manufactured through a process of foaming in an oven. In addition, since a large amount of a foaming agent and a foaming stabilizer are used, there is a problem of an increase in cost and environmental pollution due to the use of chemicals.

Accordingly, there has been a demand for improvement of commercial properties in which the flooring material manufacturing process is excellent, the cushioning property, comfort and sound insulation effect of the flooring material are improved, and the appearance is finished neatly.

Republic of Korea Patent Publication No. 10-2007-0059811 Republic of Korea Patent Publication No. 10-2003-0018670

In order to solve the above problem, the present inventors have studied a method of manufacturing a flooring material with improved physical properties by optimizing the extrusion foaming process conditions, but manufacturing a flooring material through an extrusion foaming process rather than a conventional calendar process, As a result, the present invention was completed.

Accordingly, an object of the present invention is to provide a flooring material having excellent restoring force and appearance characteristics, and a method for manufacturing the same.

In order to achieve the above object, the present invention is a foam layer; a printed layer formed on the foam layer; and a transparent layer formed on the printed layer, wherein the residual indentation rate is less than 10%, providing a flooring material.

The present invention also comprises the steps of: a) extruding and foaming a composition for a foaming layer comprising a polyvinyl chloride (PVC) resin and a foaming agent to prepare a foaming layer;

b) preparing a printing layer by transferring a composition for a printing layer comprising a polyvinyl chloride (PVC) resin;

c) preparing a transparent layer by extruding a composition for a transparent layer comprising a polylactic acid (PLA) resin; and

d) heat-sealing the foam layer, the printed layer, and the transparent layer in order to form a flooring material; it provides a method for producing a flooring material, including.

The flooring material according to the present invention can improve productivity by shortening the manufacturing process of the flooring material through the extrusion foaming process instead of the conventional oven-type foaming process.

In addition, by controlling the extrusion and foaming process speed of the flooring material, it is possible to improve the appearance characteristics by minimizing the surface defects of the manufactured flooring material.

1 is a schematic diagram of a flooring material according to the present invention.
Figure 2 shows a manufacturing process diagram of the flooring material according to the present invention.
3 is an optical micrograph of a longitudinal cross-section of the flooring material prepared in Examples 2 and 3;

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout.

Hereinafter, the flooring material according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

flooring

1 shows a cross-sectional view of a flooring material according to the present invention. Flooring according to the present invention is a foam layer (10); a printed layer 20 formed on the 　foam layer; and a transparent layer 30 formed on the 　printing layer, wherein 2.0 parts by weight or less of the foam stabilizer is included in the foaming layer relative to 100 parts by weight of the polyvinyl chloride (PVC) resin, and the residual indentation rate is less than 10%. can

In the present invention, the flooring material may have a residual indentation ratio (KS M 3802) of less than 10%, or 5% or less, or 4% or less, and when it exceeds the above range, the improvement of the stability of the flooring material may be insignificant. In addition, the lower limit thereof is not limited, but may be 0.5% or more or 1% or more as an example. Such a residual indentation rate may be controlled by the viscoelasticity of the resin used in the foaming layer and the volume expansion ratio in the foaming layer manufacturing process. The volume expansion ratio is a ratio of the volume _{after foaming (V) to the volume before foaming (V 0} ), and the volume expansion ratio may be preferably less than 3.0.

In accordance with KS M 3802, a load of 222N is applied with a hemispherical steel bar having a diameter of 19mm and released after 5 minutes, and then, when 1 hour has elapsed, the residual indentation is performed through the change in the thickness of the foam as shown in Equation 1 below. rate can be found.

<Formula 1>

Residual indentation = (T ₀ - T ₁ )/T ₀ X 100%

T ₀ : thickness before pressing

T ₁ : Thickness after pressing

The flooring material according to the present invention may further include a fabric layer.

The fabric layer is a portion in contact with the bottom, and in order to secure rigidity, it is preferable that the thickness is constant, the dimensional stability is high, and it is not deformed by heat and pressure. The fabric layer may be a woven or nonwoven fabric including at least one of cotton, nylon, polyester and rayon.

The flooring material according to the present invention includes a foam layer (10).

The foam layer 10 may be formed from a foam layer composition including a polyvinyl chloride (PVC) resin and a foaming agent. The foaming layer 10 can be formed by mixing a polyvinyl chloride resin and a foaming agent to prepare a foamed layer composition, which is then extruded and foamed to be described later. The foam layer composition may include polyvinylidene chloride (PVDC) resin, chlorinated polyvinyl chloride (CPVC) resin, etc. in addition to polyvinyl chloride resin and foaming agent. The foam layer 10 may be formed on the bottom or the fabric layer.

The blowing agent is azodicarbonamide (ADCA, Azodicarbonamide), p,p'-oxybisbenzenesulfonyl hydrazide (p,p'-Oxybis(benzenesulfonyl hydrazide)), p-toluenesulfonyl hydrazide (p- toluenesulfonyl hydrazide) and sodium bicarbonate, but is not limited thereto. After the foaming agent is foamed, it may have a volume increase ratio of 100 to 500% by volume. In the process of foaming, the gas generated from the foaming agent may form bubbles, thereby forming foamed cells in the foaming layer 10 . The foamed cell may be a spherical foamed cell, and all of the walls of the pores are formed in a closed structure, so that the pores are not connected to other pores, and are also referred to as closed cells or closed cells. Since the foam cell is not deformed in shape by a physical external force, it is possible to improve soft properties and cushioning of the foam layer 10 .

In addition, the foaming layer 10 of the present invention contains a foaming stabilizer derived from the foaming agent in addition to the polyvinyl chloride (CPVC) resin. Since the foaming stabilizer is a metal salt, when used in a large amount, there is a problem such as environmental pollution.

In the present invention, by improving the foaming process to be described later, the amount of the foaming agent and foaming stabilizer used in the foaming process is minimized. Specifically, the content of the foaming stabilizer included in the foaming layer is 100 weight of polyvinyl chloride (PVC) resin. It may be 2.0 parts by weight or less, preferably 1.5 parts by weight or less, more preferably 1.0 parts by weight or less, and most preferably 0.6 parts by weight or less.

As the foam stabilizer, a lead-based stabilizer, a Ca-Zn-based stabilizer, a Ba-Zn-based stabilizer, a tin-based stabilizer, or the like may be used. Specifically, lead-based stabilizers include tribasic lead sulphate (TLS), dibasic lead phosphite (DLP), dibasic lead stearate (DLS), lead stearate, etc. Can be used. In addition, as the Ca-Zn-based stabilizer, a mixture of calcium stearate and zinc stearate, a mixture of calcium carboxylate and zinc carboxylate, or the like can be used. Further, as the Ba-Zn-based stabilizer, a mixture of barium stearate and zinc stearate, a mixture of barium carboxylate and zinc carboxylate, or the like can be used. In addition, as a tin-based stabilizer, mercaptide tin salt, laurate tin salt, malate tin salt, and the like can be used.

The thickness of the foam layer formed through the foaming process may be 0.1 to 2.0 mm, preferably 0.8 to 1.2 mm.

When the thickness of the foam layer is less than 0.1 mm, the cushioning feeling of the flooring material may be reduced because the thickness is thin, and there is a problem in that the pattern of the floor or the fabric layer is exposed on the product surface. Conversely, when the thickness exceeds 2.0 mm, when the flooring material is bent for a long time, the shape of the foam cell is deformed and fixed, and deep wrinkles may be generated on the surface of the product.

The flooring according to the present invention includes a printed layer (20).

The printing layer 20 is formed on the foam layer 10 and includes various patterns, and serves to impart aesthetics to the flooring material.

The printing layer 20 may be manufactured by a transfer printing method in which a polymer film having a printed pattern formed thereon is transferred onto a thermoplastic resin. The polymer may be polyethylene terephthalate (PET).

The print layer 20 may include a thermoplastic resin including polyvinyl chloride (PVC) resin.

Specifically, the printing layer 20 is a thermoplastic resin, and includes a polyvinyl chloride (PVC: Poly Vinyl Chloride) resin, and additionally a polystyrene (PS: Poly Styrene) resin, acrylonitrile butadiene (ABS: Acrylonitrile Butadiene). Styrene) resin, polylactic acid (PLA: Poly Lactic Acid) resin, polyethylene phthalate (PET: Polyethylene Terephthalate) resin, polyolefin (PO: Poly Olefine) resin, may further include any one or more of an acrylic (acrylic) resin.

The thickness of the printed layer 20 may be 0.3 to 1.0 mm. If the thickness of the printed layer 20 is less than 0.3 mm, printing may be difficult, and if it exceeds 1.0 mm, there is a problem in that curling occurs in the upward direction, and the cost of manufacturing the flooring material may increase.

The flooring material according to the present invention includes a transparent layer (30).

The transparent layer 30 is formed on the printed layer 20 to give a sense of volume, and serves to protect the pattern formed on the upper surface of the printed layer 20 .

The transparent layer 30 may be formed from a composition for the transparent layer, and the composition for the transparent layer may be processed by crosslinking-modified polylactic acid (PLA) resin composition.

The crosslinking-modified PLA resin composition is modified through a crosslinking reaction upon thermal initiation, and may include a PLA resin, a thermal initiator, and a crosslinking monomer. Specifically, the crosslinking-modified PLA resin composition may include 0.1 to 10 parts by weight of a thermal initiator and 0.1 to 10 parts by weight of a crosslinking monomer based on 100 parts by weight of the PLA resin.

In addition, the crosslinking-modified PLA resin composition may further include at least one of a nonphthalate-based plasticizer, a lubricant, calcium carbonate, and titanium dioxide. Specifically, the crosslinking-modified PLA resin composition is based on 100 parts by weight of the PLA resin, 5 to 100 parts by weight of a nonphthalate-based plasticizer, 0.1 to 10 parts by weight of a lubricant, 5 to 1000 parts by weight of calcium carbonate, and 0.5 to 50 parts by weight of titanium dioxide It may further include one or more of the parts.

At this time, PLA (Polylactic acid) resin is a main material of biodegradable resin, and is a thermoplastic polyester of lactide or lactic acid. For example, it can be prepared by polymerizing lactic acid produced by fermenting starch extracted from corn, potatoes, etc. have. Since the corn, potatoes, etc. are renewable plant resources, the PLA resin that can be secured from them can effectively cope with the problem caused by the depletion of petroleum resources.

In addition, PLA resin _{emits much less environmentally harmful substances such as CO 2} during use or disposal compared to petroleum-based materials such as polyvinyl chloride (PVC), and is an eco-friendly property that can be easily decomposed under natural conditions even when discarded. have

PLA resin can be divided into crystalline PLA (c-PLA) resin and amorphous PLA (a-PLA) resin. At this time, in the case of a crystalline PLA resin, it is preferable to use an amorphous PLA resin because a bleeding phenomenon may occur in which the plasticizer flows out to the surface of the sheet. In the case of using an amorphous PLA resin, there is an advantage in that the compatibilizer, which was essentially added in order to prevent the bleeding phenomenon, does not need to be added. When using an amorphous PLA resin, the PLA resin is most preferably 100% amorphous PLA resin, and if necessary, a PLA resin in which crystalline and amorphous coexist can be used.

In addition, the crosslinking-modified PLA resin composition may include a thermal initiator in order to cause the PLA resin to undergo a crosslinking reaction by heat. The thermal initiator is preferably a radical initiator that is decomposed by heat generated during processing such as plywood processing to form radicals. Specifically, benzoic peroxide, dialkyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, dicumene hydroperoxide, t-butylperoxy-2-ethylhexanoate, t-butylperoxybenzoate It is preferably at least one selected from ate, azobisdimethylvaleronitrile, and azobisisobutyronitrile, but is not limited thereto.

The content of the thermal initiator is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the PLA resin, but is not limited thereto. When the content of the thermal initiator is less than 0.1 parts by weight, it is difficult for a sufficient radical initiation reaction to occur, and when the content of the thermal initiator exceeds 10 parts by weight, the PLA resin may be deteriorated by the unreacted initiator, and the physical properties may be reduced.

In addition, the crosslinking-modified PLA resin composition may include a crosslinking monomer serving as a crosslinking formed between molecular chains of the PLA resin by a crosslinking reaction.

It is preferable that the crosslinking monomer has excellent properties such as melt strength, transparency, UV stability, water resistance, solvent resistance, etc. required for polymer polymerization, and is easily polymerized by heat. Specifically, it is preferably at least one selected from among acrylate-based monomers and methacrylate-based monomers having a monofunctional or polyfunctional group, but is not limited thereto.

The content of the crosslinking monomer is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the PLA resin, but is not limited thereto. At this time, when the content of the crosslinking monomer is less than 0.1 parts by weight, there is a problem that the effect of improving physical properties such as melt strength is insufficient. When the content of the crosslinking monomer exceeds 10 parts by weight, there is a problem of compatibility with other materials constituting each layer. The overall physical properties of each layer may be deteriorated.

The thickness of the transparent layer 30 may be 0.1 to 0.5 mm. If the thickness of the transparent layer 20 is less than 0.1 mm, it may be difficult to protect the printed layer, and if it exceeds 0.5 mm, transparency may be lowered and the aesthetics of the flooring material may not be good.

The polyvinyl chloride (PVC) resin used in the foam layer 10 and the printed layer 20 of the present invention may be soft PVC. Specifically, the polyvinyl chloride (PVC) resin used in the foam layer 10 and the printed layer 20 of the present invention has a plasticizer content of 20 parts by weight or more, specifically 50 parts by weight, based on 100 parts by weight of the polyvinyl chloride resin. to 100 parts by weight of soft PVC.

The flooring material according to the present invention includes a surface treatment layer (not shown).

The surface treatment layer is formed on the transparent layer 30, and improves scratch resistance, stain resistance and surface properties, and provides an environmentally friendly effect. Such a surface treatment layer may be formed using those commonly used in the industry.

Method of manufacturing flooring

Figure 2 shows a manufacturing process diagram of the flooring material according to the present invention.

A method for manufacturing a flooring material according to the present invention,

a) preparing a foamed layer by extruding and foaming a composition for a foaming layer comprising a polyvinyl chloride (PVC) resin and a foaming agent; b) preparing a printing layer by transferring a composition for a printing layer comprising a polyvinyl chloride (PVC) resin; c) preparing a transparent layer by extruding a composition for a transparent layer comprising a polylactic acid (PLA) resin; and d) heat-sealing the foam layer, the printed layer, and the transparent layer in order to form a flooring material.

First, the method for manufacturing a flooring material according to the present invention includes the step a) of preparing a foaming layer by extruding and foaming a composition for a foaming layer including a polyvinyl chloride (PVC) resin and a foaming agent.

The composition for the foaming layer may include 0.1 to 5 parts by weight of a foaming agent, more preferably 0.5 to 2 parts by weight, based on 100 parts by weight of the polyvinyl chloride resin. When the foaming agent is included in less than 0.1 parts by weight, the foaming ratio may not come out as much as desired. Conversely, when it exceeds 5.0 parts by weight, over-foaming may occur, resulting in destruction of the foam cell structure and deterioration of physical properties.

The foam layer composition may further include a foaming agent stabilizer to control the foaming agent during foaming. The foam stabilizer may include 0.1 to 2.0 parts by weight of the foam stabilizer based on 100 parts by weight of the polyvinyl chloride resin. In addition, for adjusting the melt strength, a plasticizer or a heat-resistant stabilizer may be further included.

Other than that, the contents of the polyvinyl chloride (PVC) resin, the foaming agent, and the foaming stabilizer are the same as described above.

Next, the method for manufacturing a flooring material according to the present invention includes a step b) of preparing a printing layer by transferring and printing a composition for a printing layer comprising a polyvinyl chloride (PVC) resin.

The composition for the printing layer includes a polyvinyl chloride (PVC) resin.

Other than that, the content of the polyvinyl chloride (PVC) resin is the same as described above.

In addition, the polyvinyl chloride (PVC) resin used in the composition for the foam layer and the composition for the printing layer may be soft PVC. Specifically, the polyvinyl chloride (PVC) resin used in the composition for a foam layer and the composition for a printing layer of the present invention may be soft PVC having a plasticizer content of 50 parts by weight or more. Specifically, the composition for the foaming layer and the composition for the foaming layer may include 50 to 100 parts by weight of a plasticizer based on 100 parts by weight of the polyvinyl chloride resin.

Next, the method for manufacturing a flooring material according to the present invention includes the step c) of extruding a composition for a transparent layer including a polylactic acid (PLA) resin to prepare a transparent layer.

The composition for the transparent layer includes polylactic acid (PLA) resin, and specifically, the composition for the transparent layer may be a cross-linked modified PLA resin composition.

Other than that, the content of the crosslinking-modified PLA resin composition is the same as described above.

Next, the method for manufacturing a flooring material according to the present invention includes the step d) of forming a flooring material by heat-sealing the foam layer, the printed layer and the transparent layer. The foam layer, the printed layer, and the transparent layer may be formed on the fabric layer.

The foam layer may be performed at a processing temperature of 150 to 210 °C. The thermal fusion process of laminating the foam layer, the printing layer and the transparent layer may be performed under the conditions of a processing temperature of 70 to 100°C. Unlike the normal foaming process, the foaming layer manufactured by extrusion foaming had to use an excess of 5 parts by weight or more of the foaming agent based on 100 parts by weight of the polyvinyl chloride resin in the conventional process, 1 part by weight based on 100 parts by weight of the polyvinyl chloride resin. Since foaming can proceed only by using the following small amount of the foaming agent, there is an advantage that various harmful impurities derived from the foaming agent can be minimized.

In addition, when the extrusion foaming, the extrusion foaming rate may be 50 to 190 rpm, preferably 100 to 190 rpm, more preferably 150 to 190 rpm. If the extrusion foaming rate is less than 50 rpm, the internal pressure and frictional heat are not sufficient to melt the material, so the foam size and shape of the cells formed by the extrusion foaming are not uniform, and if it exceeds 190 rpm, the speed during the extrusion foaming process is high and the internal frictional heat This rises and over-foaming may occur, resulting in surface defects. In this case, the extrusion foaming speed means the speed of the screw driven during extrusion foaming, that is, the extrusion foaming screw.

The thermal fusion may be performed at a temperature of 70 to 100° C. for 15 to 60 seconds. The heat-sealing temperature and time are optimized in consideration of the adhesive force and physical properties between each layer.

The method for manufacturing a flooring material according to the present invention may further include; step e) of forming a surface treatment layer after step d), if necessary.

Step e) is performed to improve scratch resistance, stain resistance and surface properties, and to provide an environmentally friendly effect, and a conventional method used in the art may be used.

As described above, the flooring material according to the present invention can improve productivity by shortening the manufacturing process of the flooring material through the extrusion foaming process instead of the conventional calendering process, and also reduces the residual indentation rate of the manufactured flooring material to less than 10%. It can be controlled to improve cushioning and resilience.

In addition, when the extrusion foaming speed is adjusted to 120 to 190 rpm in the manufacturing process of the flooring material according to the present invention, it is possible to minimize the surface defects of the manufactured flooring material, thereby improving the marketability.

Hereinafter, preferred examples are presented to help the understanding of the present invention, but the following examples are merely illustrative of the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, It goes without saying that changes and modifications fall within the scope of the appended claims.

Examples: Example 1 and Comparative Examples 1 to 2

(1) Manufacture of flooring

[Production Example 1]

As a composition for a foaming layer, 0.5 parts by weight of a foaming agent (azodicarbonamide) and 1.0 parts by weight of a foaming stabilizer (a 1:1 mixture of barium carboxylate and zinc carboxylate) were prepared by mixing with respect to 100 parts by weight of the polyvinyl chloride resin.

A polyvinyl chloride resin was used as the composition for the printing layer.

As a composition for a transparent layer, 5 parts by weight of a dialkyl peroxide as a thermal initiator and 5 parts by weight of a methacrylate-based monomer as a crosslinking monomer with respect to 100 parts by weight of PLA resin (Nature works, 2003D) prepared.

[Production Example 2]

With respect to 100 parts by weight of the polyvinyl chloride resin, 5 parts by weight of a foaming agent (azodicarbonamide) and 2.0 parts by weight of a foaming stabilizer (a 1:1 mixture of barium carboxylate and zinc carboxylate) were mixed to prepare a composition for a foaming layer.

A polyvinyl chloride resin was used as the composition for the printing layer.

As a composition for a transparent layer, 5 parts by weight of a dialkyl peroxide as a thermal initiator and 5 parts by weight of a methacrylate-based monomer as a crosslinking monomer with respect to 100 parts by weight of PLA resin (Nature works, 2003D) prepared.

[Example 1]

The foam layer composition of Preparation Example 1 was processed at a temperature of 210° C. through an extrusion foaming process to form a foam layer having a thickness of 1.0 mm. Subsequently, the printed layer and the transparent layer prepared to have a thickness of 0.3 mm and 0.2 mm, respectively, were heat-sealed at a temperature of 100° C. in the order of the foaming layer/printed layer/transparent layer to prepare a flooring material.

At this time, the barrel temperature of the extrusion foaming device Labtech Engineering, PVC Cast Film Line was 210°C, the die temperature was 200°C, and the extrusion and foaming speed was 50 rpm.

[Example 2]

A flooring material was prepared in the same manner as in Example 1, except that the extrusion foaming rate was 110 rpm.

[Example 3]

A flooring material was prepared in the same manner as in Example 1, except that the extrusion foaming rate was 170 rpm.

[Comparative Example 1]

A flooring material was prepared in the same manner as in Example 1, except that the extrusion foaming rate was 200 rpm.

[Comparative Example 2]

A fabric layer was prepared by cutting a nonwoven fabric of a fabric material to a thickness of 0.5 m. After performing a calendering process to form a pre-foaming layer on the fabric layer with the composition for the foaming layer of Preparation Example 2, it was foamed at a temperature of 220° C. to form a foamed layer having a thickness of 0.3 mm. Then, a rotary screen process was performed to form a printed layer by applying a polyvinyl chloride resin as a composition for a printing layer on the foam layer by a rotating screen roller.

Experimental Example 1: Measurement of flooring properties according to extrusion and foaming rate

The physical properties of the flooring material according to the extrusion and foaming screw speed were measured for the flooring material to which the foamed layer prepared by extrusion foaming was applied.

Table 1 below shows the results of the extrusion and foaming process conditions and the draw ratio, surface state, density, volume expansion ratio, and residual indentation ratio of the prepared flooring material in Examples 1 to 3 and Comparative Example 1 when manufacturing the flooring material.

The volume expansion ratio means the ratio of the volume before foaming (V ₀ ) to the volume after foaming (V).

For the foaming state, the longitudinal section of the flooring material was observed using an optical microscope (Leica Microsystem, S6D). If the cell shape included in the foam layer was uniform, it was evaluated as “good”, and if the cell shape was non-uniform, it was evaluated as “bad”.

Extrusion foaming speed
(rpm) draw ratio surface condition density
(g/cc) volume expansion ratio
(V/V ₀ ) Residual indentation rate
(%) Example 1 50 1.5 Good 0.5305 1.69 9.52 Example 2 110 1.5 Good 0.5720 1.58 8.20 Example 3 170 1.5 Good 0.5669 1.59 6.12 Comparative Example 1 200 1.5 bad - - not measurable

Referring to Table 1, when the extrusion and foaming speed is 200 rpm, it was found that the surface state was poor, which was due to the high speed during the extrusion and foaming process, so that the internal frictional heat increased and the over-foaming phenomenon occurred, resulting in surface defects.

3 is an optical micrograph of a longitudinal cross-section of the flooring material prepared in Examples 2 and 3;

Referring to FIG. 3 , it can be seen that the foam size and shape of the flooring material of Example 2 (110 rpm) were relatively uneven compared to the flooring material of Example 3 (170 rpm). When the rpm is low during the extrusion and foaming process, the internal pressure and frictional heat are not sufficient to melt the material, so the cell shape is non-uniform.

10: foam layer
20: printed layer
30: transparent layer

Claims (13)

foam layer;
a printed layer formed on the foam layer; and
a transparent layer formed on the printed layer; and
A flooring material having a residual indentation of less than 10%. According to claim 1,
A surface treatment layer formed on the transparent layer; further comprising a flooring material. According to claim 1,
The foaming layer comprises a polyvinyl chloride (PVC) resin, a foaming agent and a foaming stabilizer. According to claim 1,
The thickness of the foam layer is 0.1 to 2.0 mm, flooring. According to claim 1,
The thickness of the printed layer is 0.3 to 1.0 mm, the flooring. 4. The method of claim 3,
The foam stabilizer is at least one selected from the group consisting of a lead-based stabilizer, a Ca-Zn-based stabilizer, a Ba-Zn-based stabilizer, and a tin-based stabilizer, flooring. a) preparing a foaming layer by extruding and foaming a composition for a foaming layer comprising a polyvinyl chloride (PVC) resin and a foaming agent;
b) preparing a printing layer by transferring a composition for a printing layer comprising a polyvinyl chloride (PVC) resin;
c) preparing a transparent layer by extruding a composition for a transparent layer comprising a polylactic acid (PLA) resin; and
d) forming a flooring material by heat-sealing the foaming layer, the printed layer and the transparent layer in order; including, a method of manufacturing a flooring material. 8. The method of claim 7,
The extrusion foaming rate during the extrusion foaming process is 50 to 190 rpm, the method of manufacturing a flooring material. 8. The method of claim 7,
The composition for the foaming layer comprises 0.1 to 5.0 parts by weight of a foaming agent, based on 100 parts by weight of the polyvinyl chloride resin. 8. The method of claim 7,
The composition for the foaming layer further comprises 0.1 to 1.0 parts by weight of a foaming stabilizer based on 100 parts by weight of the polyvinyl chloride resin. 8. The method of claim 7,
The extrusion foaming method, further comprising 0.1 to 1.0 parts by weight of a foam stabilizer, based on 100 parts by weight of the polyvinyl chloride resin. 8. The method of claim 7,
The extrusion foaming is performed under the conditions of a foaming layer processing temperature of 150 to 210 ℃, a method of manufacturing a flooring material. 8. The method of claim 7,
After step d), e) forming a surface treatment layer; further comprising, a method of manufacturing a flooring material.

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