JP7657866B2 - Polyvinyl chloride-based artificial leather without foam structure and its manufacturing method - Google Patents

Description

The present invention relates to polyvinyl chloride-based artificial leather, and in particular to polyvinyl chloride-based artificial leather that does not have a foam structure and a method for producing the same.

Polyvinyl chloride (PVC) is the main raw material in the production and development of artificial leather, which is widely used in automotive interiors.
Polyvinyl chloride having a high degree of polymerization has a high melting temperature and low melt fluidity, which makes it difficult to process.

In order to improve the melt flowability of polyvinyl chloride, lower the processing temperature, and facilitate the production processing, it is necessary to add a plasticizer to the polyvinyl chloride material.
However, the phthalate plasticizers used in conventional technology can emit a pungent odor, and the addition of other additives, such as blowing agents, during the processing of PVC can also emit a pungent odor.

In order to improve the surface properties of the artificial leather, the surface of the synthetic leather is usually subjected to a surface treatment.
Existing surface treatment methods mainly use solvent-based surface treatment agents, but the solvent-based surface treatment agents have a problem of high odor index.
Artificial leather that has been subjected to existing surface treatments has an odor level of 4.0 or higher when measured based on PV3900C3, a general automobile odor test method, which significantly affects the comfort of the user.
Furthermore, prior art polyvinyl chloride-based artificial leather (also called PVC artificial leather) typically includes a dense surface layer and a foam layer to provide a leather feel.
However, since the existing foam layer has a foam structure formed by a foaming agent, it may still emit an irritating odor.

In the technical field of polyvinyl chloride artificial leather, development is needed to further reduce the odor level of polyvinyl chloride artificial leather so as to improve the in-car environment, and at the same time, it is necessary to maintain a certain level of tear strength of the artificial leather.
This can meet the requirements of most mid-range or luxury vehicles.

The technical problem that this invention aims to solve is to address the shortcomings of the prior art by providing a polyvinyl chloride-based artificial leather that does not have a foam structure and a method for producing the same.

In order to solve the above technical problems, the present invention provides a polyvinyl chloride-based artificial leather that does not have a foamed structure, which includes a base layer and a surface layer formed directly on the base layer.
A substantial structure formed of the facing composition is formed so as to extend from a surface of the facing layer remote from the base layer into the base layer.
The facing composition includes 30 to 60 parts by weight of a polyvinyl chloride resin, 30 to 60 parts by weight of a polymeric plasticizer having a first weight average molecular weight of 1,500 to 6,000, and 0.01 to 5 parts by weight of a graphene material.
The molecular structure of the polymeric plasticizer contains at least one straight-chain soft segment.
The soft segment contains an ether group.
The concentration of the soft segment containing the ether group in the polymer plasticizer is 20 wt % or more, and the surface potential of the graphene material is −5 mV (millivolts) to −50 mV.

In order to solve the above technical problems, the present invention provides a method for producing a polyvinyl chloride-based artificial leather that does not have a foamed structure.
The method for producing the polyvinyl chloride-based artificial leather not having a foamed structure includes: mixing a graphene material and a polymer plasticizer to obtain a first mixed material; mixing the first mixed material and a polyvinyl chloride resin to obtain a second mixed material; rolling and dispersing the second mixed material to obtain a graphene premix sheet material; further mixing the graphene premix sheet material, additional polyvinyl chloride resin, and additional polymer plasticizer to obtain a surface composition; mixing and high-temperature melting the surface composition and rolling it to form a surface layer; and further bonding the surface layer to a base layer.
The molecular structure of the polymeric plasticizer contains at least one straight-chain soft segment.
The soft segment contains an ether group.
The concentration of the soft segment containing the ether group in the polymer plasticizer is 20 wt % or more, and the surface potential of the graphene material is −5 mV (millivolts) to −50 mV.

As an effect of the present invention, the polyvinyl chloride-based artificial leather without a foam structure and the manufacturing method thereof according to the present invention have the following technical features: "The outer material composition includes 30 to 60 parts by weight of polyvinyl chloride resin, 30 to 60 parts by weight of a polymer plasticizer having a first weight average molecular weight of 1,500 to 6,000, and 0.01 to 5 parts by weight of a graphene material," and "The molecular structure of the polymer plasticizer includes at least one linear soft segment. The soft segment contains an ether group. The concentration of the soft segment containing the ether group in the polymer plasticizer is 20 wt % or more, and the surface potential of the graphene material is -5 mV (millivolts) to -50 mV." Due to these technical features, the odor level of polyvinyl chloride-based artificial leather is improved, and even without a foam structure, the touch of leather can be provided, and the graphene material has excellent tear strength.

FIG. 1 is a schematic diagram of a laminated structure of a polyvinyl chloride-based artificial leather according to the prior art. 1 is a schematic diagram of a laminated structure of the polyvinyl chloride-based artificial leather of the present invention. 1 is a flowchart of a method for producing a polyvinyl chloride-based artificial leather of the present invention.

To better understand the features and technical contents of the present invention, please refer to the following detailed description of the present invention and the accompanying drawings.
However, the accompanying drawings provided are only for reference and explanation, and are not intended to limit the scope of the present invention.

Hereinafter, the embodiments of the present invention will be described with reference to certain specific embodiments, so that those skilled in the art can understand the advantages and effects of the present invention based on the contents disclosed in this specification.
The present invention can be implemented or applied by other different specific embodiments, and each detail in the specification can be modified and changed in various ways based on different viewpoints and applications without departing from the concept of the present invention.
As will be explained in advance, the accompanying drawings of the present invention are simple schematic illustrations and are not drawn to actual size.
The technical contents of the present invention will be described in more detail based on the following embodiments, but the scope of protection of the present invention is not limited to the disclosed contents.

It should be understood that although the present specification may use terms such as "first,""second," and "third" to describe various materials or parameters, these materials or parameters are not limited by these terms.
Furthermore, the term "or" as used herein may include any one or more combinations of the associated listed items, depending on the actual circumstances.

[Vinyl chloride-based artificial leather]
In order to solve the above-mentioned technical problems in the conventional art, an embodiment of the present invention provides a polyvinyl chloride artificial leather 100.
In particular, the present invention provides a polyvinyl chloride-based artificial leather 100 that does not have a foam structure.
The polyvinyl chloride-based artificial leather 100 according to the present invention can provide the leather feel required for ordinary artificial leathers, even though it does not have a foam structure.

The odor level of the polyvinyl chloride-based artificial leather 100 according to the embodiment of the present invention, measured based on the automobile odor test method PV3900C3, is level 3.5 or less, and more preferably level 3.0 or less.
That is, compared to the conventional technology, the polyvinyl chloride-based artificial leather 100 according to the embodiment of the present invention has a low odor level, so that it can satisfy the comfort level and health needs of general consumers when using products.
In addition, the polyvinyl chloride-based artificial leather 100 according to the embodiment of the present invention has improved tear strength.

As shown in FIG. 1, a polyvinyl chloride-based artificial leather 100a according to the conventional technology includes, from bottom to top, a base layer 1a, a foamed layer 2a, a surface layer 3a, and a selectively applied surface treatment layer 4a.
Here, in the conventional technology, the foam layer is usually formed with a foaming agent to create a foam structure so as to provide a leather feel.

As shown in FIG. 2, unlike the conventional technology, the polyvinyl chloride-based artificial leather 100 according to the embodiment of the present invention includes, from bottom to top, a base fabric layer 1, a top fabric layer 2, and a selectively applied surface treatment layer 3.

The surface layer 2 is formed directly on one surface of the base layer 1 , and the surface treatment layer 3 is formed on a surface of the surface layer 2 remote from the base layer 1 .
It should be noted that the polyvinyl chloride-based artificial leather 100 according to the embodiment of the present invention does not have a foam structure.

More specifically, a substantial structure (i.e., the main structure of the surface layer 2 ) is formed so as to extend from the surface of the surface layer 2 remote from the base layer 1 to the base layer 1 .
The surface layer 2 has a substance that is in direct contact with the base layer 1 so that there is no foam layer between the surface layer 2 and the base layer 1 .
The surface layer 2 has a non-foamed structure and does not include foam structures such as foam pores, and thus provides a leather feel.

It should be explained that the term "solid structure" as used herein refers to a continuous resin structure that is not foamed with a foaming agent and does not contain foam pores.
However, during the manufacturing process of artificial leather, due to factors such as the compatibility between different polymeric materials or added materials, or the parameters of the manufacturing method, the actual structure may contain a small number of pores, but these are not foam pores caused by foaming.

To achieve the above object, the substance of the surface layer 2 according to the embodiment of the present invention is formed of a fabric composition.
The surface composition includes a polyvinyl chloride resin, a polymer plasticizer, and a graphene material.

The amount of the polyvinyl chloride resin used is 30 to 60 parts by weight, preferably 30 to 50 parts by weight, based on 100 parts by weight of the total weight of the surface composition.
The amount of the polymer plasticizer used is 30 to 60 parts by weight, preferably 30 to 50 parts by weight, based on 100 parts by weight of the total weight of the surface composition.
In addition, the amount of the graphene material used is 0.01 to 5 parts by weight, preferably 0.01 to 1 part by weight, based on 100 parts by weight of the total weight of the surface composition.

To explain further, the polyvinyl chloride resin is a matrix for the outer material composition to provide the mechanical strength required for the artificial leather.
The polymeric plasticizer is a plasticizer having a high molecular weight, which not only improves the odor level of the artificial leather but also gives the surface layer 2 a leather feel.
In addition, the graphene material can provide the tear strength of the material after the outer layer composition is introduced, and has excellent tear strength even when the outer layer 2 has a thickness thinner than that of artificial leather with a conventional foam structure.

In one embodiment of the present invention, the polyvinyl chloride resin has a weight average molecular weight (Mw) of 30,000 g/mol to 200,000 g/mol and a glass transition temperature (Tg) of 80°C to 85°C.

In one embodiment of the present invention, the first weight average molecular weight of the polymer plasticizer is 1,500 g/mol to 6,000 g/mol, and preferably 2,000 g/mol to 5,000 g/mol.

More specifically, the molecular structure of the polymer plasticizer includes a linear soft segment, and the soft segment has an ether group.
Here, the concentration of the soft segment containing the ether group in the polymer plasticizer is 20 wt % or more, preferably 20 wt % to 40 wt %, and particularly preferably 20 wt % to 30 wt %.
The soft segment having an ether group may be composed of, for example, diethylene glycol (DEG).
The glass transition temperature of the polymer plasticizer is -15°C to -80°C, and preferably -40°C to -80°C.
The thickness D of the substantial structure of the surface layer 2 is 100 μm to 600 μm, and preferably 150 μm to 550 μm, but the present invention is not limited to this.

With the above-mentioned configuration, the polymer plasticizer is used as a substitute for conventional low molecular weight plasticizers, and the use of a foaming agent can be avoided, so not only does it improve the odor level of the polyvinyl chloride-based artificial leather, but the molecular structure of the polymer plasticizer (ether group soft segment) also gives the surface layer 2 of the polyvinyl chloride-based artificial leather 100 a leather-like feel.

In addition, since the polymeric plasticizer has a relatively high surface tension, the polymeric plasticizer has better dispersibility for the graphene material, so that the graphene material can be dispersed in the surface composition even when no other dispersant (e.g., polyethylene glycol PEG) is used.

It is noteworthy that when the concentration of the soft segment having an ether group in the polymer plasticizer is set to 20 wt % or more, it provides the graphene material with better dispersibility, which is advantageous for improving the tear strength.
When the concentration of the soft segment having an ether group in the polymer plasticizer is less than 20 wt %, the effect of improving the tear strength of the graphene material in the surface composition is not significant.

In one embodiment of the present invention, the soft segment having an ether group is incorporated into the middle or end of the molecular structure of the polymer plasticizer.

The soft segment having the ether group is in the main chain of the molecular structure of the polymer plasticizer, and does not exist in the form of a side chain.

The polymer plasticizer is a polymer polyester formed by a polycondensation reaction between a dibasic acid raw material and a dihydric alcohol raw material.
The soft segment having an ether group is composed of at least one of the dibasic acid raw material and the dihydric alcohol raw material.

In one embodiment of the present invention, the dibasic acid raw material is at least one selected from the group consisting of adipic acid (AA), maleic acid (MA), sebacic acid, and dodecanedioic acid.

The dihydric alcohol is at least one selected from the group consisting of diethylene glycol (DEG), triethylene glycol (TEG), tetraethylene glycol, polytetrahydrofuran (PTMG), 1,2-propylene glycol (1,2-PG), 2-methyl-1,3-propanediol (MPO), neopentyl glycol (NPG), and 1,4-cyclohexanedimethanol (CHDM).

The polymeric plasticizer is terminated with an end-capped fatty alcohol to stop the polycondensation reaction.
The end-capped fatty alcohol is a monoalcohol, and the end-capped fatty alcohol is at least one of the group consisting of isooctyl alcohol (2-EH), 2-propyl-1-heptanol (2-PH), lauryl alcohol, diethylene glycol monobutyl ether (DGBE), and diethylene glycol methyl ether (DGME).

For example, the dibasic acid raw material for synthesizing polymeric plasticizers is adipic acid (AA).
The dihydric alcohol raw material for synthesizing the polymer plasticizer can selectively be diethylene glycol or other types of dihydric alcohols (eg, 2-methyl-1,3-propanediol (MPO)).
Additionally, the end-capping fatty alcohol for terminating the polycondensation reaction may be diethylene glycol methyl ether (DGME) and/or isooctyl alcohol (2-EH).

As described above, the graphene material is added to the surface composition, thereby improving the tear strength, and the polymer plasticizer serves to disperse the graphene material.
It is worth noting that in this embodiment, the surface potential of the graphene material is between −5 mV (millivolts) and −50 mV, and preferably between −10 mV and −30 mV.
Thereby, the graphene material can be effectively dispersed in the surface composition due to the above-mentioned surface potential characteristics and polymeric plasticizer.

Here, the surface potential of the graphene material may be referred to as a Zeta potential.
Zeta potential is intended to indicate the electrical potential that a nanoscale material has at its sliding surface, and is usually expressed in units of millivolts (mV).
Zeta potential can be measured, for example, by employing electrophoresis (laser Doppler method) in which an electric field is applied to a nanoscale material in a solution, causing electrophoretic movement of charged particles, and the zeta potential can be determined by observing this electrophoretic movement.

In one embodiment of the present invention, the graphene material may be, for example, at least one of expanded graphene (EG) and graphene oxide, but the present invention is not limited thereto.

To further explain, the surface composition further comprises 10 parts by weight or less of processing aids.

Here, the processing aid is a linear aliphatic dibasic acid ester.
The processing aid also has a second weight average molecular weight that is 300-800.
That is, the weight average molecular weight of the processing aid is lower than the weight average molecular weight of the polymeric plasticizer.

In one embodiment of the present invention, the processing aid is at least one selected from the group consisting of bis(2-ethylhexyl) sebacate (DOS), di-2-ethylhexyl adipate (DOA), diisononyl adipate (DINA), diisodecyl adipate (DIDA), and diisononyl sebacate (DINS).

With the above-mentioned configuration, the processing aid can improve the processability of the surface material composition by reducing the viscosity of the surface material composition.
The processing aid also functions as a plasticizer and improves the feel of the leather of the surface layer.

In one embodiment of the present invention, the outer material composition further provides 0.5 to 5 parts by weight of a stabilizer to enhance the heat stability of the rubber and reduce the odor level of the artificial leather.

Here, the stabilizer is at least one selected from the group consisting of lithium stearate, magnesium stearate, calcium stearate, barium stearate, zinc stearate, magnesium laurate, barium laurate, zinc laurate, calcium ricinoleate, barium ricinoleate, zinc ricinoleate, and zinc caprylate.

Here, the stabilizer is preferably a metal soap compound such as calcium ricinoleate, barium ricinoleate, or zinc ricinoleate.

In one embodiment of the present invention, the facing composition further comprises 0 to 10 parts by weight of a filler.
The filler is an inorganic particulate material.

Here, the filler may be selected from the group consisting of calcium carbonate, silicon dioxide, alumina, clay, talc, diatomaceous earth, and metal oxides such as fertilizer, glass, carbon black, and metal fibers and powders, glass balls, graphite, aluminum hydroxide, barium sulfate, magnesium oxide, magnesium carbonate, and magnesium silicate. At least one selected from the group consisting of calcium silicate and calcium silicate.
Here, the filler is preferably calcium carbonate, but the present invention is not limited thereto.

In one embodiment of the present invention, the facing composition further comprises 2 to 8 parts by weight of a flame retardant.

Here, the flame retardant may be an inorganic compound such as aluminum hydroxide, magnesium hydroxide, antimony trioxide, or zinc borate; or an inorganic compound such as cresyl diphenyl phosphate, tris(2-chloroethyl) phosphate, tris(1-chloropropane-2-yl) phosphate, or tris(1-methyl-2-chloroethyl) phosphate. tris(2-chloro-1-methylethyl) ester); and halogen compounds such as chlorinated paraffin wax.
Here, the flame retardant is preferably antimony trioxide, but the present invention is not limited thereto.

It is worth noting that in one embodiment of the present invention, the facing composition does not include a blowing agent (e.g., a chemical or physical blowing agent).
The surface layer 2 of the embodiment of the present invention can provide the leather feel required for ordinary artificial leather, provided that it does not have a foamed structure or does not use a foaming agent.

In other words, the use of a foaming agent or the irritating odor caused by the foam structure can be avoided with this invention.

It is worth noting that the polymeric plasticizer in the surface composition can serve to disperse the graphene material.
Preferably, the facing composition does not include any dispersants.
For example, the facing composition does not include a polyethylene glycol (PEG) dispersant.

Continuing, as shown in FIG. 2, the base layer 1 may be, for example, a woven or non-woven fabric.
The surface layer 2 may be formed of an artificial leather similar to natural leather by forming the base layer 1 made of a base fabric by artificial synthesis, for example.

More specifically, the polyvinyl chloride-based artificial leather 100 includes a surface treatment layer 3 .
The surface treatment layer 3 is formed on the surface of the surface layer 2 separated from the base layer 1 by coating with an aqueous surface treatment agent.
The surface treatment layer 3 can improve the gloss, feel, light resistance, heat resistance, stain resistance, abrasion resistance, and scratch resistance of the polyvinyl chloride-based artificial leather 100 .

The surface of the surface treatment layer 3 away from the surface layer 2 can be hot embossed to form different patterns on the surface of the artificial leather.

In this embodiment, the aqueous surface treatment agent is an aqueous polyurethane-based treatment agent that does not contain N-ethylpyrrolidone.
As a result, the formulation of the surface treatment layer 3 can also reduce the odor level of the polyvinyl chloride-based artificial leather 100, thereby improving the comfort of the user.

With the above-mentioned configuration, the polyvinyl chloride-based artificial leather 100 without a foamed structure according to the embodiment of the present invention can be applied to automobile interiors.
For example, door panels, instrument panels, consoles, columns, seat back panels, seat fabrics, etc.
Of course, the polyvinyl chloride-based artificial leather without a foam structure according to the embodiment of the present invention can be applied to other fields similar to automobile interiors.

[Manufacturing method of vinyl chloride-based artificial leather]
The above is a description of the structural and material features of the polyvinyl chloride-based artificial leather not having a foamed structure according to the embodiment of the present invention.
Also, an embodiment of the present invention provides a method for producing a polyvinyl chloride-based artificial leather.
The method for producing the polyvinyl chloride-based artificial leather includes steps S110, S120, S130, and S140.
It should be noted that the order and operation of each step in this embodiment can be adjusted according to needs and is not limited thereto.

Step S110 is to carry out a pre-dispersion operation of the graphene material.
The step S110 includes mixing a graphene material and a polymeric plasticizer to obtain a first mixed material while the graphene material is pre-dispersed in the polymeric plasticizer for a first time.

Here, the graphene material and the polymer plasticizer may be vibrated, for example, in a water bath environment of an ultrasonic vibrator (40 kHz, 50 W) for a vibration time of 15 to 45 minutes (preferably, 25 to 35 minutes).
The water bath temperature of the ultrasonic vibrator is controlled to 40°C to 60°C, and preferably 45°C to 55°C.

In an embodiment of the present invention, the surface potential of the graphene material is between −5 mV (millivolts) and −50 mV, preferably between −10 mV and −30 mV.
The molecular structure of the polymer plasticizer includes a linear soft segment, and the soft segment has an ether group.
The concentration of the soft segment containing an ether group in the polymer plasticizer is 20 wt % or more, preferably 20 wt % to 40 wt %, and particularly preferably 20 wt % to 30 wt %.

The step S110 further includes mixing the first mixed material containing the graphene material and the polymer plasticizer with a polyvinyl chloride resin (e.g., PVC powder) to obtain a second mixed material, and rolling and dispersing the second mixed material using a three roll mill to perform a second pre-dispersion of the graphene material and obtain a graphene premix sheet material.

Here, in the graphene premix sheet material, the graphene material content is 5 wt% to 15 wt%, the polymer plasticizer content is 30 wt% to 50 wt% (preferably 35 wt% to 45 wt%), and the polyvinyl chloride resin content is 40 wt% to 60 wt% (preferably 45 wt% to 55 wt%).

The step S120 is to carry out an operation of producing a surface composition.
The step S120 includes further mixing the graphene premix sheet material, additional polyvinyl chloride resin, additional polymeric plasticizer, and optionally adding other additives (e.g., processing aids, stabilizers, fillers, flame retardants) to obtain a surface composition.
That is, the facing composition includes at least a polyvinyl chloride resin, a polymeric plasticizer, a graphene premix sheet material, and other additives.

The amount of the polyvinyl chloride resin used is 30 to 60 parts by weight, preferably 30 to 50 parts by weight, based on 100 parts by weight of the total weight of the surface composition.
The amount of the polymer plasticizer used is 30 to 60 parts by weight, preferably 30 to 50 parts by weight, based on 100 parts by weight of the total weight of the surface composition.
In addition, the amount of the graphene premix sheet used is 0.5 parts by weight to 10 parts by weight, and preferably 2 parts by weight to 8 parts by weight, based on 100 parts by weight of the total weight of the surface composition.

It is worth noting that, when the graphene material contained in the graphene premix sheet material (the content of the graphene material in the graphene premix sheet material is about 5 wt % to 15 wt %) is further converted, the amount of the graphene material used in the surface composition is about 0.01 to 5 parts by weight, and preferably 0.01 to 1 part by weight, but the present invention is not limited thereto.

The step S130 is to perform an operation of forming a surface layer.
The step S130 includes mixing and high-temperature melting the surface composition and rolling it to form a surface layer.
More specifically, the surface composition is mixed and melted at high temperature in a small mixer and a Banbury mixer in this order, and then rolled in a rolling mill to form the surface composition into a surface layer.

The step S140 is to perform an operation of forming an artificial leather.
The step S140 includes laminating the surface layer to the base layer through a rolling machine, and then applying and drying an aqueous polyurethane-based treatment agent to the surface of the surface layer to form a surface treatment layer, thereby completing the manufacture of a polyvinyl chloride-based artificial leather.

[Measurement of experimental data]
The present invention will be described in detail below with reference to experimental data. However, these examples are provided for the purpose of understanding the present invention, and the present invention is not limited thereto.

<Preparation Example 1>
The surface composition of Preparation Example 1 shown in the table below was mixed and melted at high temperature in a small mixer and a Banbury mixer in that order, and then the surface composition was rolled using a rolling mill to form the surface composition as a surface layer. The surface layer was then bonded to the base layer by rolling, and an aqueous polyurethane-based treatment agent was applied to the surface of the surface layer and dried to form a surface treatment layer.
The physicochemical properties of the polyvinyl chloride-based artificial leather of Preparation Example 1 were measured, and the results are shown in Table 1 below.
It should be noted that the surface composition of Preparation Example 1 did not contain any graphene premix sheet, i.e., did not contain any graphene material.

Example 1
The graphene material and the polymer plasticizer were mixed and vibrated for 30 minutes using an ultrasonic vibrator (40 kHz, 50 W) (the water bath temperature was controlled at 50° C.) to obtain a first mixed material.
Next, polyvinyl chloride resin (PVC powder) was added to the first mixed material to obtain a second mixed material.
Next, the second mixed material was rolled and dispersed using a three-roll mill to obtain a graphene premix sheet material (I).
Here, the parameters relating to the polymer plasticizer material were the same as those in Preparation Example 1, and for example, the concentration (wt %) of the soft segment having an ether group was 22.5 wt %.
In the graphene premix sheet material (I), the content of the graphene material was 10 wt %, the content of the polymer plasticizer was 40 wt %, and the content of polyvinyl chloride (PVC powder) was 50 wt %.
The surface potential of the graphene material was −20 mV (with an error of ±10).
In Example 1, based on the formulation of the surface layer composition of Example 1 described in Table 1 below, the graphene premix sheet material (I) was added to the surface layer composition, and the surface layer composition was mixed and melted at high temperature in a small mixer and a Banbury mixer in this order. Next, the surface layer was rolled by a rolling machine to form the surface layer as the surface layer, and the surface layer was bonded to a base layer by rolling. Then, an aqueous polyurethane-based treatment agent was applied to the surface of the surface layer and dried to form a surface treatment layer.
The physicochemical properties of the polyvinyl chloride-based artificial leather of Example 1 were measured, and the results are shown in Table 1 below.
It is noteworthy that in the surface composition of Example 1, a graphene material was added.

<Preparation Example 2>
The surface composition of Preparation Example 2 shown in the table below was mixed and melted at high temperature in a small mixer and a Banbury mixer in that order, and then the surface composition was rolled using a rolling mill to form the surface composition as a surface layer. The surface layer was then bonded to the base layer by rolling, and an aqueous polyurethane-based treatment agent was applied to the surface of the surface layer and dried to form a surface treatment layer.
The physicochemical properties of the polyvinyl chloride-based artificial leather of Preparation Example 2 were measured, and the results are shown in Table 1 below.
It should be noted that the surface composition of Preparation Example 2 did not contain any graphene premix sheet, i.e., did not contain any graphene material.

<Comparative Example 1>
The graphene material and the polymer plasticizer were mixed and vibrated for 30 minutes using an ultrasonic vibrator (40 kHz, 50 W) (the water bath temperature was controlled at 50° C.) to obtain a first mixed material.
Next, polyvinyl chloride resin (PVC powder) was added to the first mixed material to obtain a second mixed material.
Next, the second mixed material was rolled and dispersed using a three-roll mill to obtain a graphene premix sheet material (II).
Here, the parameters relating to the polymer plasticizer material were the same as those in Preparation Example 2, and for example, the concentration (wt %) of the soft segment having an ether group was 15.0 wt %.
In the graphene premix sheet material (II), the content of the graphene material was 10 wt %, the content of the polymer plasticizer was 40 wt %, and the content of polyvinyl chloride (PVC powder) was 50 wt %.
In <Comparative Example 1>, based on the formulation of the surface material composition of Comparative Example 1 described in Table 1 below, graphene premix sheet material (II) was added to the surface material composition, and the surface material composition was mixed and melted at high temperature in a small mixer and a Banbury mixer in this order. Next, the surface material composition was rolled by a rolling machine to form the surface material composition as a surface layer, and the surface layer was bonded to a base layer by rolling. Finally, an aqueous polyurethane-based treatment agent was applied to the surface of the surface layer and dried to form a surface treatment layer.
The physicochemical properties of the polyvinyl chloride-based artificial leather of Comparative Example 1 were measured, and the results are shown in Table 1 below.

In Comparative Example 2, a polymer plasticizer containing a soft segment having an ether group was not used, and a conventional foam structure was adopted.
The plasticizer used was a phthalate ester plasticizer.

Next, the physicochemical properties of the produced polyvinyl chloride-based artificial leathers were measured to obtain the physicochemical properties of the polyvinyl chloride-based artificial leathers.
Physicochemical properties include, for example, odor level, tensile strength, and tear strength.
Here, the odor level was measured based on PV3900C3, a common automobile odor test method, at 80°C for 2 hours.
The odor level system includes six levels.
1 = no odor.
2 = There is an odor, but it is not bothersome.
3 = Odor is noticeable but not unpleasant.
4 = unpleasant odor.
5 = Strong unpleasant odor.
6 = There is an unbearable odor.
Here, the tensile strength was measured based on ASTM D412.
Tear strength was measured according to ASTM D624.

[Table 1] Experimental conditions and measurement results

[Consideration of measurement results]
According to the experimental results, by using the polymer plasticizer in Example 1, it is possible to obtain an optimized molecular weight range and excellent compatibility with polyvinyl chloride resin (PVC), as well as excellent cold resistance and feel.
Example 1 showed a significant improvement in odor level compared to Comparative Example 2 in which no polymer plasticizer was used.

In addition, in Example 1, the graphene material was dispersed by using a soft segment having an ether group with a concentration of 22.5%.
According to the experimental results, Example 1 was able to significantly improve the tensile strength and tear strength under the above conditions.
For example, the MD tensile strength was improved from 569 N/3 cm to 605 N/3 cm, the CD tensile strength was improved from 506 N/3 cm to 525 N/3 cm, the MD tear strength was improved from 34 N/3 cm to 38 N/3 cm, and the CD tear strength was improved from 38 N/3 cm to 40 N/3 cm.

On the other hand, in Comparative Example 1, the graphene material was dispersed by using a soft segment having an ether group with a concentration of 15.0%.
According to the experimental results, in Comparative Example 1, the improvement in tensile strength and tear strength under the above conditions is not significant.

[Advantageous Effects of the Embodiments]
As an effect of the present invention, the polyvinyl chloride-based artificial leather not having a foamed structure and the manufacturing method thereof according to the present invention have the following technical features: "The surface composition comprises 30 to 60 parts by weight of polyvinyl chloride resin, 30 to 60 parts by weight of a polymer plasticizer having a first weight average molecular weight of 1,500 to 6,000, and 0.01 to 5 parts by weight of a graphene material" and "The molecular structure of the polymer plasticizer contains at least one linear soft segment. The soft segment contains an ether group. The concentration of the soft segment containing the ether group in the polymer plasticizer is 20 wt % or more, and the surface potential of the graphene material is -5 mV (millivolts) to -50 mV." Due to these technical features, the odor level of polyvinyl chloride-based artificial leather can be improved, and even without a foamed structure, the feel of leather can be provided, and the graphene material has excellent tear strength.

The above disclosure is merely a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto.
Therefore, all equivalent technical modifications made by utilizing the contents of the specification and drawings of the present invention are included within the scope of the claims of the present invention.

<Prior Art>
100a...Polyvinyl chloride-based artificial leather 1a...Base layer 2a...Foam layer 3a...Surface layer 4a...Surface treatment layer <Example of the present invention>
100...Polyvinyl chloride-based artificial leather 1...Base layer 2...Surface layer 3...Surface treatment layer D...Thickness

Claims (10)

A base layer;
A polyvinyl chloride-based artificial leather having no foam structure, comprising: a surface layer formed directly on the base layer;
A substantial structure formed of a surface composition is formed so as to extend from a surface of the surface layer away from the base layer to the base layer,
The surface composition includes 30 to 60 parts by weight of a polyvinyl chloride resin, 30 to 60 parts by weight of a polymer plasticizer that is a polymer polyester having a first weight average molecular weight of 1,500 to 6,000, and 0.01 to 5 parts by weight of a graphene material;
The molecular structure of the polymer polyester contains at least one linear soft segment,
The soft segment contains an ether group,
The concentration of the soft segment containing an ether group in the polymer plasticizer is 20 wt % or more,
A polyvinyl chloride-based artificial leather having no foam structure, characterized in that the surface potential of the graphene material is -5 mV (millivolts) to -50 mV. The concentration of the soft segment containing an ether group in the polymer plasticizer is 20 wt % to 40 wt %;
The soft segment is composed of diethylene glycol,
2. The polyvinyl chloride-based artificial leather having no foamed structure according to claim 1, wherein the surface composition does not contain a polyethylene glycol dispersant. The polyvinyl chloride-based artificial leather without a foam structure according to claim 1, wherein the graphene material is at least one of expanded graphene (EG) and graphene oxide (Graphene Oxide). The polyvinyl chloride-based artificial leather without a foam structure according to claim 1, wherein the outer composition further comprises 15 parts by weight or less of a processing aid, 0.5 to 5 parts by weight of a stabilizer, 0 to 15 parts by weight of a filler, and 2 to 8 parts by weight of a flame retardant. The processing aid is a linear aliphatic dibasic acid ester,
the processing aid has a second weight average molecular weight that is from 300 to 800;
5. The polyvinyl chloride-based artificial leather having no foamed structure according to claim 4, wherein the surface composition does not contain a foaming agent. Mixing a graphene material and a polymer plasticizer, which is a polymer polyester, to obtain a first mixed material, mixing the first mixed material and a polyvinyl chloride resin to obtain a second mixed material, and rolling and dispersing the second mixed material to obtain a graphene premix sheet material;
Further mixing the graphene premix sheet material, the additional polyvinyl chloride resin, and the additional polymeric plasticizer to obtain a surface composition;
The surface composition is mixed and melted at a high temperature, and then rolled to form a surface layer, and the surface layer is then bonded to a base layer.
The molecular structure of the polymer polyester contains at least one linear soft segment,
The soft segment contains an ether group,
The concentration of the soft segment containing an ether group in the polymer plasticizer is 20 wt % or more,
A method for producing a polyvinyl chloride-based artificial leather not having a foamed structure, characterized in that the surface potential of the graphene material is -5 mV (millivolts) to -50 mV. In the graphene premix sheet material, the content of the graphene material is 5 wt % to 15 wt %,
The content of the polymer plasticizer is 30 wt % to 50 wt %;
7. The method for producing a polyvinyl chloride-based artificial leather having no foamed structure according to claim 6, wherein the content of the polyvinyl chloride resin is 40 wt % to 60 wt %. The total weight of the surface composition is 100 parts by weight,
The amount of polyvinyl chloride resin used is 30 parts by weight to 60 parts by weight,
The amount of the polymer plasticizer used is 30 parts by weight to 60 parts by weight,
The method for producing a polyvinyl chloride-based artificial leather not having a foamed structure according to claim 6, wherein the amount of the graphene material used is 0.01 to 5 parts by weight. The graphene material and the polymeric plasticizer are vibrated in a water bath environment of an ultrasonic vibrator for a vibration time of 15 minutes to 45 minutes;
7. The method for producing a polyvinyl chloride-based artificial leather having no foamed structure according to claim 6, wherein the temperature of a water bath of the ultrasonic vibrator is controlled to 40°C to 60°C. 7. The method for producing a polyvinyl chloride-based artificial leather having no foamed structure according to claim 6, further comprising forming a surface treatment layer by applying and drying an aqueous polyurethane-based treatment agent on the surface of the surface layer, thereby completing the production of the polyvinyl chloride-based artificial leather.