KR20210121506A - Skin material for automobile interior materials and manufacturing method thereof - Google Patents

Abstract

The present invention relates to an outer shell material for a vehicle interior material and a method for manufacturing the same, and specifically, to an outer shell material for a vehicle interior material and a method for manufacturing the same, wherein a two-tone outer shell material for a vehicle interior material includes a first outer shell layer and a second outer shell layer having a color different from that of the first outer shell layer, is easy to process and has an excellent appearance.

Description

Skin material for automobile interior materials and manufacturing method thereof

The present invention relates to a skin material for an automobile interior material and a method for manufacturing the same, and more particularly, from top to bottom, comprising: a first skin layer; and a second epidermal layer of a color different from that of the first epidermal layer; A two-tone car interior skin material containing

In general, the skin material of automobile interior materials such as instrument panel, door trim, floor console, and arm rest is manufactured by powder slush molding method that has the effect of maintaining the embossing pattern do.

On the other hand, in recent years, as the quality of life has increased, consumer demand for automobile interior materials having an excellent appearance is increasing. In order to satisfy such consumer needs, for example, it is trying to manufacture a two-tone skin material for interior materials of automobiles by breaking away from one-tone.

As an example for manufacturing the two-tone car interior material, Republic of Korea Patent Publication No. 10-1215587 (published on December 26, 2012, hereinafter 'Patent Document') is powder slush molding of the first resin. A powder slush molding machine and powder for forming a two-color molded sheet by coating a part of a mold to form an application layer, and then powder slush molding a sheet-shaped object made of a second resin different from the first resin on the upper portion of the application layer A slush molding method is disclosed.

However, the above patent document does not disclose at all about the flow characteristics of the composition itself used to form the coating layer, conditions for implementing the same, and the like.

In addition, when the first resin is applied to a part of the powder slush molding mold to form an application layer in order to manufacture a two-tone car interior skin material, the low-viscosity first resin flows down in the mold, resulting in in-mold coating properties. There was a problem in that the esthetic was deteriorated, such as the thickness of the coating layer of the skin material for the interior material of the vehicle lowered and finally completed was uneven, and the appearance was uneven.

KR 10-1215587 B (Announcement Date: 2012.12.26)

The present invention provides an excellent appearance while easy processability, from top to bottom, a first skin layer; and a second epidermal layer of a color different from that of the first epidermal layer; An object of the present invention is to provide a skin material for a two-tone automobile interior material comprising a, and a method for manufacturing the same.

In order to achieve the above object,

The present invention from top to bottom, the first epidermal layer; and a second epidermal layer of a color different from that of the first epidermal layer; As a skin material for automobile interior materials comprising:

The first skin layer comprises a filler,

In the car interior material, the average value of the color difference (ΔE) between the reference point and any five points is 0.5 or less (CIELAB (1976) color space, D65 light source, SCI measurement method) To provide a skin material for automobile interior materials.

In addition, the present invention provides a first epidermal layer forming step of forming a first epidermal layer; and

a second epidermal layer forming step of forming a second epidermal layer under the first epidermal layer; A method for manufacturing a skin material for automobile interior materials comprising:

The first skin layer comprises a filler,

In the car interior material, the average value of the color difference (ΔE) between the reference point and any five points is 0.5 or less (CIELAB (1976) color space, D65 light source, SCI measurement method) A method for manufacturing a skin material for an automobile interior is provided.

Specifically, the present invention from top to bottom, the first epidermal layer; and a second epidermal layer of a color different from that of the first epidermal layer; It relates to a two-tone skin material for an automobile interior material and a method for manufacturing the same, comprising: widening the particle size distribution of the solid content in the spray coating composition for manufacturing the first skin layer to facilitate the spray process and provide excellent in-mold coating properties. It is an object of the present invention to provide a skin material for automobile interiors having excellent processability and excellent appearance of a finished skin material, and a method for manufacturing the same.

The skin material for an automobile interior material of the present invention and a method for manufacturing the same have excellent processability and excellent appearance.

1 is a side cross-sectional view schematically showing a two-tone car interior skin material.
2 is a graph showing the particle size distribution of the filler used in the present invention.
Figure 3a is a graph showing the particle size distribution of the composition for spray coating of Example 1 according to the present invention.
FIG. 3B is a diagram illustrating the analysis of the cumulative distribution (Q3(x)) of the graph of FIG. 3A .
Figure 4a is a graph showing the particle size distribution of the composition for spray coating of Comparative Example 3.
FIG. 4B is a diagram illustrating the analysis of the cumulative distribution (Q3(x)) of the graph of FIG. 4A .

The present invention from top to bottom, the first epidermal layer 100; and a second epidermal layer 200 having a color different from that of the first epidermal layer; As a skin material (1) for automobile interior materials comprising:

The first skin layer 100 includes a filler,

In the car interior material 1, the average value of the color difference (ΔE) between the reference point and any five points is 0.5 or less (CIELAB (1976) color space, D65 light source, SCI measurement method) It relates to a skin material for an automobile interior (see FIG. 1).

Hereinafter, each layer will be described in detail.

first epidermal layer (100)

The first skin layer 100 of the present invention is formed by spray coating a spray coating composition on a part of a powder slush molding mold, and has a color different from that of the second skin layer 200 to be described later, and the second skin layer 200 . It is partially formed on the upper part to give a two-tone effect to the car interior material.

Regarding the composition for spray coating, the inventors of the present invention initially proposed a composition for spray coating in order to solve the disadvantages of the conventional low-viscosity spray coating composition in which the in-mold coating property is lowered due to low adhesion to the powder slush molding mold. Although the viscosity was prepared to have a high viscosity, when the viscosity of the composition for spray coating is increased in this way, the spray coating composition is sprayed under the pressure condition of the nozzle (for example, about 0.3 Mpa, shear rate: 10 ⁵ -10 ⁶ 1/s) There was a problem in that the spray fairness was deteriorated because it did not work well.

As a result, the inventors of the present invention focused on research to solve the above problems. As a result, when the particle size distribution of the solid content in the composition for spray coating is widened, the viscosity is low at the time of spraying (that is, in the high shear region) and the application to the mold is completed. After (that is, in the low shear region), it was confirmed that the spray process was easy and excellent in-mold coating properties were obtained due to high viscosity and shear thinning flow characteristics.

Specifically, the composition for spray coating for implementing the above effect may include 100 parts by weight of a polyvinyl chloride resin (a), 61-95 parts by weight of a plasticizer (b), and 2.5-20 parts by weight of a filler (c).

Hereinafter, the composition for spray coating for preparing the first epidermal layer 100 will be described in detail for each component.

(a) polyvinyl chloride resin

The polyvinyl chloride resin (a) may be a mixed polyvinyl chloride resin in which polyvinyl chloride resins having different average particle diameters are mixed.

In the present invention, the average particle diameter means the diameter of the particle in the case of a perfect spherical shape, and in the case of a shape other than a spherical shape, it means the average length of the major axis when divided into a major axis and a minor axis.

Specifically, the polyvinyl chloride resin (a) of the present invention has an average particle diameter of 0.1-3 μm, preferably a paste polyvinyl chloride resin (a ₁ ) having an average particle diameter of 0.3-2 μm and an average particle diameter of 15-40 μm , preferably a straight (straight) polyvinyl chloride resin (a ₂ ) of 19-35 μm may be mixed.

The paste polyvinyl chloride resin (a ₁ ) may be a resin having pseudoplastic flow characteristics in which the viscosity decreases as the shear rate increases. More specifically, the paste polyvinyl chloride resin (a ₁ ) having the above pseudoplastic flow characteristics has a viscosity of 8,000-9,500 cps at a shear rate of 0.1 (1/s), and a viscosity of 4,000 at a shear rate of 1,000 (1/s). It can be -6,000cps.

The viscosity of the paste polyvinyl chloride resin may be measured at 25° C. using a rheometer (TA Instruments, AR2000) after mixing the polyvinyl chloride resin and a plasticizer (Diisononyl phthalate) in equal amounts for 1 hour.

In addition, the straight polyvinyl chloride resin (a ₂ ) is mixed with the paste polyvinyl chloride resin (a ₁ ) to further lower the viscosity of the spray coating composition.

The weight ratio of the paste polyvinyl chloride resin (a ₁ ) and the straight polyvinyl chloride resin (a ₂ ) may be 60-90: 10-40, preferably 70-85: 15-30, and the straight When the polyvinyl chloride resin (a ₂ ) is mixed below the above range, the viscosity of the composition for spray coating increases in the high shear region, thereby reducing spray processability, and when mixing in excess of the above range, in the composition for spray coating The dispersion stability of the straight polyvinyl chloride resin (a ₂ ) may be lowered, and thus the storability of the composition for spray coating may be reduced, and thus may be mixed within the above range.

The average particle size may be obtained by diluting a polyvinyl chloride resin to 0.01 wt % in ethanol to prepare a sample, and then measuring it using a particle size meter (Malvern, Zetasizer Nano ZS90).

In addition, the polyvinyl chloride resin (a) of the present invention may have a polymerization degree of 700-2500, preferably 1200-2000, but is not limited thereto.

The degree of polymerization was measured at a temperature of 30°C according to ASTM D1243.

(b) plasticizer

The plasticizer (b) is for plasticizing the polyvinyl chloride resin (a) to facilitate coating of the composition for spray coating on a mold, and includes a phthalate-based plasticizer, a terephthalate-based plasticizer, a benzoate-based plasticizer, and a citrate-based plasticizer. It may be at least one selected from the group consisting of a plasticizer, a glycol-based plasticizer, a trimellitate-based plasticizer, a phosphate-based plasticizer, an adipate-based plasticizer, and an epoxy-based plasticizer.

The phthalate-based plasticizer is, for example, diethylhexyl phthalate, diisononyl phthalate, diisodecyl phthalate, dimethyl phthalate, diethyl phthalate, dibutyl phthalate, diheptyl phthalate, dioctyl phthalate, dinonyl phthalate and ditridecyl phthalate. It may be one or more selected from the group consisting of, but is not limited thereto.

The terephthalate-based plasticizer may be, for example, dioctyl terephthalate, but is not limited thereto.

The benzoate-based plasticizer is, for example, 2-(2-(2-phenylcarbonyloxyethoxy)ethoxy)ethyl benzoate, glyceryl tribenzoate, trimethylolpropane tribenzoate, isononyl benzoate, 1- consisting of methyl-2-(2-phenylcarbonyloxypropoxy)ethyl benzoate, 2,2,4-trimethyl-1,3-pentanediol dibenzoate, n-hexyl benzoate and trimethylol propanetribenzoate It may be one or more selected from the group, but is not limited thereto.

The citrate-based plasticizer may be, for example, at least one selected from the group consisting of acetyltributyl citrate, tributylcitrate, acetyltriethylhexyl citrate and triethylhexyl citrate, but is not limited thereto.

The glycol-based plasticizer may be, for example, at least one selected from the group consisting of ethylene glycol and propylene glycol, but is not limited thereto.

The trimellitate-based plasticizer may be, for example, at least one selected from the group consisting of triisobutyl trimellitate, trinomaloctyl trimellitate, trioctyl trimellitate and triisononyl trimellitate, but is not limited thereto. it is not

The phosphate-based plasticizer may be, for example, at least one selected from the group consisting of tricresyl phosphate and tributyl phosphate, but is not limited thereto.

The adipate-based plasticizer may be, for example, at least one selected from the group consisting of bis(2-ethylhexyl) adipate, dimethyl adipate, monomethyl adipate, dioctyl adipate, and diisononyl adipate, However, the present invention is not limited thereto.

The epoxy-based plasticizer may be, for example, epoxidized soybean oil, but is not limited thereto.

The plasticizer (b) may be used in an amount of 61-95 parts by weight, preferably 75-90 parts by weight, based on 100 parts by weight of the polyvinyl chloride resin (a), and when it is less than 61 parts by weight, the viscosity of the composition for spray coating increases Spray processability may be reduced, and when it exceeds 95 parts by weight, gelling properties after coating may be reduced, and plasticizer migration may occur, and thus may be used within the above range.

In the present invention, as a specific embodiment of the plasticizer (b), a trimellitate-based plasticizer capable of improving the migration resistance of the plasticizer by being environmentally friendly and having excellent thermal stability and an epoxy-based plasticizer having excellent heat resistance can be mixed and used. . In this case, based on 100 parts by weight of the polyvinyl chloride resin (a), the trimellitate plasticizer is 60-85 parts by weight, preferably 65-80 parts by weight, and the epoxy plasticizer is 1-10 parts by weight, preferably 2 parts by weight. -8 parts by weight may be used.

(c) fillers

The filler (c) is to widen the particle size distribution of the solid content in the composition for spray coating so that the composition for spray coating can have a high viscosity in the low shear region, and has an average particle diameter of 0.85 μm or less, preferably 0.8 μm or less. It may be an inorganic filler, and the lower limit thereof is not limited, but may be, for example, 0.03 μm or more, preferably 0.05 μm or more (see FIG. 2 ).

The average particle diameter of the filler (c) may be measured by diluting the filler to 0.01 wt% in ethanol to prepare a sample, and then measuring it using a particle size meter (Malvern, Zetasizer Nano ZS90).

When the average particle diameter of the filler (c) exceeds 0.85 μm, the significance of widening the particle size distribution of the solid content is lowered, and after application to the mold is completed (low shear region), the composition flows down, and the in-mold coatability may be reduced. , the surface smoothness of the first epidermal layer 100 may be lowered, and thus may have an average particle diameter within the above range.

The filler is, for example, at least one selected from the group consisting of calcium carbonate, wood powder, mica, amorphous silica, talc, zeolite, magnesium carbonate, calcium sulfate, calcium phosphate, magnesium phosphate, aluminum oxide, kaolin, aluminum hydroxide and talc. In the present invention, as a specific embodiment, inexpensive calcium carbonate may be used.

In addition, the filler (c) may be used in an amount of 2.5-20 parts by weight, preferably 3-15 parts by weight, more preferably 5-10 parts by weight, based on 100 parts by weight of the polyvinyl chloride resin (a), 2.5 If the amount is less than 20 parts by weight, the composition may flow down after application to the mold is completed (low shear region) and the in-mold coating property may be deteriorated. If it exceeds 20 parts by weight, it may not be suitable for molding the composition for spray coating. can be used within

In addition, the composition for spray coating may further include a solvent (d) in addition to the polyvinyl chloride resin (a), the plasticizer (b), and the filler (c) described above.

The solvent (d) is for lowering the viscosity of the composition for spray coating in the high shear region, and may be at least one selected from the group consisting of hydrocarbon-based, ketone-based, ester-based and alcohol-based solvents.

In addition, the solvent (d) may be used in an amount of 5-40 parts by weight, preferably 10-35 parts by weight, based on 100 parts by weight of the polyvinyl chloride resin (a), and within the above range, for spray coating in the high shear region By lowering the viscosity of the composition, there is an effect of excellent spray processability.

In addition, the composition for spray coating optionally includes one or more additives selected from the group consisting of pigments, antioxidants, flame retardants, antistatic agents, light stabilizers, heat stabilizers, release agents, defoamers, leveling agents, dispersants and adhesion promoters. can do.

Since the additive may use a conventional kind used in the art, the kind is not particularly limited in the present invention, and the content thereof is also not limited as long as it does not impair the purpose of the present invention.

For the production of the first epidermal layer 100, the composition for spray coating having the above configuration has a viscosity of 6,000-20,000cps, preferably at 21-26°C, 1-5rpm, in an embodiment, 25°C, 2rpm. may be 8,000-15,000cps, and has an excellent in-mold coating property because it has a high viscosity in a low shear region within the above range, and thus has excellent adhesion to the mold.

In addition, the composition for spray coating may have a viscosity of 500-3,000 cps, preferably 1,000-2,500 cps, in the conditions of 21-26° C., 18-25 rpm, in one embodiment, 25° C., 20 rpm, within the above range. There is an excellent effect of spray processability by having a low viscosity in the high shear region.

The viscosity may be measured using a Brookfield viscometer (BROOKFIELD AMETEK, DV3T Rheometer, #63 spindle).

In addition, the composition for spray coating of the present invention may have a thixotropy index of 3-15, preferably 3.5-10, and within the above range, the spray process is easy and the in-mold coating property is excellent. .

In the present invention, thixotropy index refers to a phenomenon in which fluidity is exhibited when an external force is applied and fluidity is lost when an external force is removed, and can be calculated from the following Equation 1.

[Equation 1]

Thixotropy index (TI) = Viscosity in the low shear region (cps) / Viscosity in the high shear region (cps)

In addition, referring to Figure 3a, the composition for spray coating can be continuously and widely distributed in the range of 0.09-20.9 μm, preferably 0.1-20 μm, the average particle diameter of the composition for spray coating is wide within the range. Since the composition may have a high viscosity in a low shear region and a low viscosity in a high shear region, the spray process is easy, and the in-mold coating property is excellent.

In addition, in the composition for spray coating, the solid content having an average particle diameter of 0.09-0.1 μm has a volume ratio with respect to the total solid content of 1.0-3.0%, preferably 1.5-2.5%, more preferably 1.6-2.0%, and the average particle diameter is The solid content of 0.1-1.0 μm may have a volume ratio of 15-35%, preferably 18-30%, more preferably 19-25% with respect to the total solid content.

In addition, in the composition for spray coating, the solid content having an average particle diameter of 1.0-5.0 μm has a volume ratio of 60-85%, preferably 65-80%, more preferably 70-75%, with respect to the total solid content, and the average particle diameter The solid content of 5.0-10.0 μm may have a volume ratio of 1-10%, preferably 1.5-5%, more preferably 2-4% with respect to the total solid content.

In addition, in the composition for spray coating, the solid content having an average particle diameter of 10.0-20.0 μm may have a volume ratio of 0.5-5%, preferably 1-3%, more preferably 1.5-2% with respect to the total solid content (Fig. see 3b).

The particle size distribution of the composition for spray coating may be obtained by diluting the composition for spray coating to 0.01 wt% in ethanol to prepare a sample, and then measuring it using a particle size meter (FRITSCH, ANALYSETTE 22 MicroTec plus).

The composition for spray coating has a wide particle size distribution so that the composition for spray coating has a high viscosity in a low shear region and a low viscosity in a high shear region. The external appearance of the skin material for automobile interior materials of the present invention including the skin layer 100 is excellent.

The first skin layer 100 of the present invention may have a thickness of 0.01-1.0 mm, preferably 0.02-0.05 mm, and within the above range, the effect of imparting a two-tone effect to the skin material 1 for automobile interior materials is effective. have.

Second epidermal layer (200)

The second skin layer 200 of the present invention is formed through a powder slush molding process using powder for powder slush molding, and has a color different from that of the first skin layer, so that a two-tone effect can be imparted to the skin material for automobile interior materials.

The powder for powder slush molding includes a core; and a core-shell structure polyvinyl chloride powder including a particle unit including a shell surrounding the core surface.

Hereinafter, the polyvinyl chloride powder for powder slush molding for forming the second skin layer 200 will be described in detail for each component.

Specifically, the core may include 50-120 parts by weight of a plasticizer based on 100 parts by weight of the straight polyvinyl chloride resin, and the shell may include 3-20 parts by weight of the paste polyvinyl chloride resin.

(A) core

(A-1) Straight polyvinyl chloride resin

The straight polyvinyl chloride resin included in the core is a homopolymer prepared by suspension polymerization, and has excellent plasticizer absorption rate.

The straight polyvinyl chloride resin may have a polymerization degree of 700-2500, preferably 1000-2000. If it is less than 700 parts by weight, mechanical properties such as elongation at break and tear strength of the skin material for automobile interior materials may be reduced. It may have a degree of polymerization within the above range.

The degree of polymerization was measured under a temperature condition of 25-32° C. in accordance with JIS K 6721-77.

In addition, the voids of the straight polyvinyl chloride resin may be 25-50%, preferably 30-40%. When it is less than 25%, the oil absorption amount of the plasticizer in the straight polyvinyl chloride resin is reduced, and when it exceeds 50%, it is difficult to manufacture the straight polyvinyl chloride resin, so it may have voids within the above range.

The void may be measured through a CPA (Cold Plasticizer Absorption) value, and the CPA may be measured according to ASTM D2396 and/or ISO 4574.

More specifically, the CPA may represent the amount of the plasticizer absorbed into the polyvinyl chloride resin at 20° C. in weight % with respect to the polyvinyl chloride resin before absorbing the plasticizer.

(A-2) plasticizer

Since the type of the plasticizer included in the core is the same as the plasticizer included in the first epidermal layer 100 described above, the overlapping description will be omitted.

The plasticizer may be used in an amount of 50-120 parts by weight, preferably 60-100 parts by weight, based on 100 parts by weight of the straight polyvinyl chloride resin (A-1). If it is less than 50 parts by weight, sufficient flexibility cannot be imparted to the straight polyvinyl chloride resin, and if it exceeds 120 parts by weight, deterioration of the physical properties of the skin material for automobile interior materials and migration of the plasticizer may occur, so it can be used within the above range.

The core may optionally further include one or more additives selected from the group consisting of heat stabilizers, lubricants, antioxidants, light stabilizers, pigments, flame retardants and antistatic agents, and conventional types used in the art may be used. Therefore, in the present invention, the type and content are not particularly limited.

For example, the additive may be 1-15 parts by weight, preferably 5-10 parts by weight, based on 100 parts by weight of the straight polyvinyl chloride resin.

(B) Shell

The shell surrounds the above-mentioned core and prevents entanglement between particles, thereby playing an important role in the future powder slush molding process.

(B-1) Paste polyvinyl chloride resin

The paste polyvinyl chloride resin contained in the shell is a homopolymer prepared by emulsion polymerization, and has excellent viscosity stability and foamability.

In addition, the paste polyvinyl chloride resin may have a polymerization degree of 700-1500, preferably 800-1400. If it is less than 700 parts by weight, mechanical properties such as elongation at break and tear strength of the skin material for automobile interior may be reduced, and if it exceeds 1500 parts by weight, the powder slush molding processability may be deteriorated, so that the polymerization degree may be within the above range.

In addition, the particle size of the paste polyvinyl chloride resin may be 0.1-20㎛, preferably 0.3-10㎛. If it is less than 0.1 μm, the flowability of the polyvinyl chloride powder is poor, and there is a difficulty in the powder slush molding process.

In addition, the paste polyvinyl chloride resin may be used in an amount of 3-20 parts by weight, preferably 5-15 parts by weight, based on 100 parts by weight of the polyvinyl chloride resin contained in the core. When it is less than 3 parts by weight, it is difficult to form a polyvinyl chloride core-shell structure, so that the flowability of the powder is lowered, thereby making the molding process difficult. Since the content of the plasticizer is reduced and the physical properties of the skin material are reduced, it can be used within the above range.

The shell may be formed to a thickness of 0.1-20 μm, preferably 0.5-10 μm. If the thickness of the shell is less than 0.1㎛, the flowability of the polyvinyl chloride powder may be reduced, and if the thickness of the shell exceeds 20㎛, the moldability is reduced, so it is preferably formed to a thickness within the above range.

The particle size of the polyvinyl chloride powder for powder slush molding may be 100-350 μm, preferably 150-250 μm. If it is less than 100㎛, the flowability of the polyvinyl chloride powder is lowered, so there is a difficulty in the powder slush molding process. can have size.

The polyvinyl chloride powder for powder slush molding is a core forming step of forming a core by mixing 50-120 parts by weight of a plasticizer with respect to 100 parts by weight of a straight polyvinyl chloride resin;

The core and 3-20 parts by weight of the paste polyvinyl chloride resin are put in a cooling mixer to form a shell enclosing the surface of the core (S3').

Hereinafter, each step will be described in detail.

Core forming step (S1')

The core forming step (S1') may be a step of forming a core by mixing a straight polyvinyl chloride resin and a plasticizer in a mixer.

Since the straight polyvinyl chloride resin and the plasticizer are the same as those described above, the overlapping description will be omitted.

In addition, the mixing can be carried out for 60-120 minutes without heating in a Henschel mixer. In this case, the powder manufacturing step is reduced compared to performing mixing in a Banbari mixer, thereby improving the production yield.

At this time, the temperature of the mixture of straight polyvinyl chloride resin and plasticizer included in the core may rise to about 120° C. due to frictional heat, and mixing is performed for the above time, so that the straight polyvinyl chloride resin through sufficient blending It is possible to increase the oil absorption of the plasticizer in the interior.

In addition, the step (S1') may optionally further include one or more additives selected from the group consisting of a heat stabilizer, a lubricant, an antioxidant, a light stabilizer, a heat resistance agent, a flame retardant, and an antistatic agent.

Shell forming step (S3')

In the shell forming step (S3'), the core prepared in the core forming step (S1') is put in a cooling mixer together with the emulsion-state paste polyvinyl chloride resin, and then shaken to form a shell surrounding the core surface. Thus, it may be a step of preparing polyvinyl chloride powder having a core-shell structure.

Since the paste polyvinyl chloride resin is the same as described above, the overlapping description will be omitted.

On the other hand, the polyvinyl chloride powder for powder slush molding of the present invention is characterized in that it does not contain a filler, and in this case, the powder slush molding formability is excellent.

More specifically, when the filler is included, the surface of the other surface (that is, the rear surface of the skin material), rather than the portion in which the second skin layer 200 comes in contact with the first skin layer 100, becomes uneven. , adhesion with the foam layer may be reduced, so the present invention is characterized in that the polyvinyl chloride powder for powder slush molding does not contain a filler.

The second skin layer 200 of the present invention formed through the powder slush molding process using the above-described powder for powder slush molding may have a thickness of 0.5-1.0 mm, preferably 0.6-0.8 mm, within the above range. As a skin material for automobile interior materials, it has excellent mechanical properties.

The skin material 1 for automobile interior materials of the present invention is an instrument panel, a door trim, a console box, an arm rest, a head rest, a pillar trim, a seat buckle, a head liner, a glove box, a trunk cover trim, an airbag cover or a steering wheel cover. It may be a skin material of parts for automobile interior materials.

In addition, in the skin material 1 for automobile interior materials of the present invention, the average value of the color difference (ΔE) between the reference point and any five points may be 0.5 or less, preferably 0.3 or less, and the lower limit thereof is not limited, but for example 0 , preferably 0.05 or more.

The average value of the color difference (ΔE) is determined according to the SCI (specular component included, specular component included) measurement method under the CIELAB (1976) color space and D65 light source after setting one point in the car interior material as a reference point. The color difference (ΔE) from the reference point was measured at five points using a colorimeter (Datacolor, CheckII).

Then, the average value of the color difference (ΔE) was calculated. (For reference, if there is a point where the color is visually distinguished from the reference point, it must be included as one of the five random points.)

In addition, in the skin material 1 for an automobile interior material of the present invention, the average value of the thickness deviation (Δ㎛) of the first skin layer measured at five arbitrary points is 15 μm or less, preferably 10 μm, more preferably 8 It may be less than μm, and the lower limit thereof is not limited, but may be, for example, 0 μm, preferably 1 μm or more.

The average value of the thickness deviation of the first epidermis layer was obtained by cutting the car interior skin material in the vertical direction, and then using a scanning electron microscope (SEM) on the side cross-section of the cut skin material at arbitrary five points. The thickness of the first epidermis layer was measured, and the deviation between these values and the target coating thickness of 30 μm was calculated and expressed as the average value thereof.

The skin material 1 for an automobile interior material of the present invention having the above characteristics has an excellent effect in appearance.

On the other hand, the present invention is a first epidermal layer forming step (S1) of forming a first epidermal layer; and

a second epidermal layer forming step (S3) of forming a second epidermal layer under the first epidermal layer; A method for manufacturing a skin material for automobile interior materials comprising:

The first skin layer comprises a filler,

In the car interior material, the average value of the color difference (ΔE) between the reference point and any five points is 0.5 or less (CIELAB (1976) color space, D65 light source, SCI measurement method) It relates to a method for manufacturing a skin material for an automobile interior material.

Hereinafter, each step will be described in detail.

First epidermal layer forming step (S1)

In the first skin layer forming step (S1), a masking jig is placed at a predetermined position in a mold for powder slush molding, a spray coating composition is spray-coated, the masking jig is removed, and then the first skin layer is gelled. It may be a step of forming (100).

The composition for spray coating can be prepared by mixing and stirring each composition described above.

In the present invention, as a specific example, after adding each composition described above to the mixer, it can be mixed for 20-40 minutes, preferably 25-35 minutes, and then 500-1,500 rpm at room temperature (20-30 ° C), Preferably, the composition for spray coating in a sol state can be prepared by stirring at a rotation speed of 800-1,200 rpm for 1-10 minutes, preferably for 5-8 minutes.

The gelling is performed while heating the powder slush molding mold to which the spray coating composition is applied to about 200-250° C. in order to form the second skin layer 200 in the second skin layer forming step (S3) described later. can

According to the present invention, the composition for spray coating for preparing the first skin layer has a wide particle size distribution, so that spray processability is easy and excellent in-mold coating properties are obtained.

Second epidermal layer forming step (S3)

The second skin layer forming step (S3) may be a step of forming the second skin layer 200 through a powder slush molding process using powder for powder slush molding.

Since the powder for powder slush molding is the same as the polyvinyl chloride powder described above, the overlapping description will be omitted.

Specifically, first, the mold for powder slush molding on which the composition for spray coating is applied is heated to about 200-250° C. At this time, the composition for spray coating is gelled to form the first skin layer 100 .

Next, the heated mold and the open container (powder box) loaded with the polyvinyl chloride powder are combined to form a closed system, and then the second skin layer 200 is under the first skin layer 100 through a powder slush molding process. can form.

Subsequently, after separating the combined mold and the open container, the second heating (post-heating) may be performed only when the polyvinyl chloride powder on the opposite side in contact with the first skin layer 100 is less melted and the molding is less.

Thereafter, after cooling the mold, the skin material for automobile interior materials including the first skin layer 100 and the second skin layer 200 of a different color from the first skin layer 100 is demolded from the mold from the top to the bottom. It is possible to manufacture a skin material for an automobile interior material.

Hereinafter, preferred examples are presented to aid 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 such variations and modifications fall within the scope of the appended claims.

[Example]

Each component used in Examples and Comparative Examples to be described later is shown in Table 1 below.

[Table 1]

1. Manufacture of skin materials for automobile interior materials

<Example 1>

First epidermal layer forming step (S1)

Poly (vinyl chloride) resin (a ₁₎ 70 parts by weight of polyvinyl chloride resin (a ₂₎ 30 parts by weight plasticizer ¹ 80 parts by weight, plasticizer ²⁵ parts by weight filler ¹⁵ parts by weight of solvent, 20 parts by weight, the pigment 3 wt. After adding parts, 5 parts by weight of a heat stabilizer, and 0.2 parts by weight of a light stabilizer to the mixer, mixing for 30 minutes, and then stirring at 25° C. for 8 minutes at a rotation speed of 1000 rpm to prepare a sol-state spray coating composition did.

Then, after placing the masking jig at a predetermined position in the mold for powder slush molding, the spray coating composition prepared above is spray coated on the mold ^{under a shear rate of 10 5} -10 ⁶ 1/s, and then the The masking jig was removed.

Then, the mold was heated to 230° C., and at this time, the composition for spray coating was gelled to form a first skin layer having a thickness of 0.03 mm.

Second epidermal layer forming step (S3)

With respect to 100 parts by weight of the straight polyvinyl chloride resin, 83 parts by weight of ^{plasticizer 1 , 5 parts by weight of plasticizer 2} , 5.5 parts by weight of heat stabilizer, 1.2 parts by weight of antioxidant, 0.5 parts by weight of light stabilizer, and 3.5 parts by weight of pigment were placed in a Henschel mixer without heating. Mix for 60-120 minutes to form the core.

Then, 9 parts by weight of the core and the paste vinyl chloride resin were put in a cooling mixer to form a shell surrounding the surface of the core, thereby preparing a polyvinyl chloride powder for powder slush molding having a core-shell structure particle size of 150-250 μm.

Next, the polyvinyl chloride powder for powder slush molding is loaded into an open container (powder box), the heated mold and the open container are combined to form a closed system, and then, through a powder slush molding process, the thickness is below the first skin layer. A second epidermal layer having a thickness of 0.75 mm is formed.

Finally, the first skin layer from top to bottom from the mold; and a second skin layer, the skin material for an automobile interior material was demolded to prepare a two-tone skin material for an automobile interior material of Example 1.

<Example 2>

^Two- tone in the same manner as in Example 1, except that in the first skin layer forming step (S1), a sol-state spray coating composition containing 7.5 parts by weight of filler 2 was used instead of 5 parts by weight of ^{filler 1} of car interior materials were manufactured.

<Comparative Example 1>

A two-tone skin material for automobile interior was prepared in the same manner as in Example 1, except that a composition for spray coating having the following composition was used in the first skin layer forming step (S1).

65 parts by weight of ^{plasticizer 1 , 5 parts by weight of plasticizer 2} , 3 parts by weight of pigment, 5 parts by weight of heat stabilizer and 0.2 parts by weight of light stabilizer with respect to 100 parts by weight of polyvinyl chloride resin (b) were added to the mixer and mixed for 30 minutes. Then, the composition for spray coating of Comparative Example 1 in a sol state was prepared by stirring at 25° C. for 8 minutes at a rotation speed of 1000 rpm.

<Comparative Example 2>

Two-tone automotive interior materials in the same manner as in Example 1, except that a sol-state spray coating composition containing 1 part by weight of ^{filler 1} was used in the first skin layer forming step (S1). A skin material was prepared.

<Comparative Example 3>

^{In the same manner as in Example 1, except that the sol-state spray coating composition containing the filler 3} was used instead of the ^{filler 1} in the first skin layer forming step (S1), the two-tone skin for automobile interior materials was used in the same manner as in Example 1. Ash was prepared.

<Comparative Example 4>

In the first skin layer forming step (S1), a composition for spray coating in a sol state containing a weight ratio of _{polyvinyl chloride resin (a 1} ) and polyvinyl chloride resin (a _{2 ) of 95:5 was used.} Except for that, a two-tone car interior material was prepared in the same manner as in Example 1.

<Reference Example 1>

A two-tone skin material for an automobile interior was prepared in the same manner as in Example 1, except that the polyvinyl chloride powder for powder slush molding prepared as follows was used in the second skin layer forming step (S3).

With respect to 100 parts by weight of the straight polyvinyl chloride resin, plasticizer ¹ 83 parts by weight, plasticizer ² 5 parts by weight, heat stabilizer 5.5 parts by weight, antioxidant 1.2 parts by weight, light stabilizer 0.5 parts by weight, pigment 3.5 parts by weight and calcium carbonate 10 parts by weight Put in a Henschel mixer and mix for 60-120 minutes without heating to form a core.

Then, 9 parts by weight of the core and the paste vinyl chloride resin were put in a cooling mixer to form a shell surrounding the surface of the core, thereby preparing a polyvinyl chloride powder for powder slush molding having a core-shell structure particle size of 150-250 μm.

2. Measurement of flow properties of compositions for spray coating

The respective viscosities and thixotropy indexes in the low shear region and high shear region of the spray coating compositions for preparing the first epidermal layer of Examples 1 to 2 and Comparative Examples 1 to 4 prepared above were measured. , the results are shown in Table 2 below.

(1) Viscosity in the low shear region: Viscosity (cps) was measured at 25° C. and 2 rpm using a Brookfield viscometer (BROOKFIELD AMETEK, DV3T Rheometer, #63 spindle).

(2) Viscosity in high shear region: Viscosity (cps) was measured at 25° C. and 20 rpm using a Brookfield viscometer (BROOKFIELD AMETEK, DV3T Rheometer, #63 spindle).

(3) thixotropy index (thixotropy index): using the viscosity measured above, it was calculated from the following formula (1).

[Equation 1]

Thixotropy index (TI) = Viscosity in the low shear region (cps) / Viscosity in the high shear region (cps)

[Table 2]

As confirmed in Table 2, the spray coating compositions of Examples 1 and 2 according to the present invention have high viscosity in the low shear region and low viscosity in the high shear region, so that the thixotropy index is 7.0 and 3.5, respectively. As a result, it could be confirmed that the thixotropic properties were exhibited.

On the other hand, it was confirmed that the composition for spray coating of Comparative Example 1 had a low viscosity in the low shear region and had a thixotropy index of 1.0, which did not have thixotropic properties.

In addition, Comparative Example 2 using a small amount of filler did not have satisfactory thixotropic properties due to low viscosity in both the high shear and low shear regions, and the spray of Comparative Example 3 using calcium carbonate having an average particle diameter exceeding a specific range as a filler The coating composition had a reduced viscosity in the low shear region, and thus it was confirmed that the thixotropy index was 1.5 and did not have thixotropic properties.

On the other hand, in _{Comparative Example 4 including the polyvinyl chloride resin (a 2} ) having a large average particle diameter in less than a specific range, the viscosity increased in the high shear region, and thus the measurement of the thixotropy index was impossible.

3. Measurement of spray processability, in-mold coating properties, and skin material properties for automobile interiors of the composition for spray coating

The spray processability of the composition for spray coating used in the first skin layer forming step (S1) and the in-mold coating property after the spray coating was completed were evaluated, and the results are shown in Table 3 below.

In addition, the appearance of the two-tone car interior material of Examples 1 to 2, Comparative Examples 1 to 4, and Reference Example 1 prepared above was measured, and the results are shown in Table 3 below.

(1) Spray fairness: When spray coating the composition for spray coating on a powder slush molding mold using a nozzle under a shear rate of ^{10 5} -10 ^{6 1/s, the degree of spraying was visually checked.} This is indicated by △ if the spraying is normal, and X if the spraying is not good.

(2) In-mold coating property: After spray coating of the spray coating composition on the powder slush molding mold was completed, the degree of adhesion of the spray coating composition to the mold was visually checked. If it does not flow, it is marked with an X.

(3) Appearance of the skin material

- The surface smoothness of the car interior material was visually checked. If the surface was smooth, it was marked as ○ (excellent appearance), and if the surface was uneven, it was marked as X (decreased appearance).

- After setting one point as a reference point in the skin material for automobile interior materials, the color difference meter (Datacolor Corporation) at 5 random points according to the SCI (specular component included) measurement method under the CIELAB (1976) color space and D65 light source. , CheckII) was used to measure the color difference (ΔE) from the reference point.

Next, the average value of the color difference (ΔE) is shown. (For reference, if there is a point where the color is visually distinguished from the reference point, it must be included as one of the five random points.)

- After cutting the skin material for automobile interior material in the vertical direction, measure the thickness of the first skin layer at 5 arbitrary points using a scanning electron microscope (SEM) on the side cross-section of the cut skin material, and After calculating the deviation between the value and the target coating thickness of 30 μm, it was expressed as an average value thereof.

[Table 3]

As confirmed in Table 3, the compositions for spray coating of Examples 1 and 2 according to the present invention have excellent in-mold coating properties while being easy to spray process, so that the color difference of the skin material for interior materials for automobiles manufactured using the compositions is easy. The average value of (ΔE) was 0.5 or less, and the average value of the thickness deviation (Δ㎛) of the first epidermis layer was 15 μm or less, confirming that the external appearance was excellent.

Specifically, in the composition for spray coating of Example 1, the solid content having an average particle diameter of 0.09 μm has a volume ratio of 1% to the total solid content, the volume ratio of the solid content having an average particle diameter of 0.1 μm is 0.8%, and the average particle diameter is 0.1-1.0 The volume ratio of solids having an average particle size of 5 to 10 μm is 20.4%, the volume ratio of solids having an average particle diameter of 1-5 μm is 72.8%, the volume ratio of solids having an average particle diameter of 5-10 μm is 3.1%, and the average particle diameter is 10-20 μm. It was confirmed that the volume ratio of the solid content was 1.9%, and the particle size distribution was wide.

On the other hand, the spray coating composition of Comparative Example 1 had normal spray processability, but it could not be adhered to the mold after coating was completed and flowed down, and it was confirmed that the in-mold coating property was lowered. The appearance of the ash is uneven and the color is uneven, the average value of the color difference (ΔE) is 0.83, and the average value of the deviation in the thickness of the first epidermis (Δ㎛) is 23㎛. It was confirmed that the aesthetics deteriorated.

In addition, the composition for spray coating of Comparative Example 2 had a very low viscosity in the high shear region, so spray processability was excellent, but it was confirmed that the in-mold coating property was deteriorated because it did not adhere to the mold after coating was completed and flowed down. The appearance of the skin material for automotive interior materials manufactured by It was confirmed that the aesthetics deteriorated.

In addition, the spray coating composition of Comparative Example 3 had normal spray processability, but it could not be attached to the mold after coating was completed and flowed down, and it was confirmed that the in-mold coating property was lowered. It was confirmed that the appearance of the ash was uneven and the color was uneven, the average value of the color difference (ΔE) was 0.53, and the average value of the deviation in the thickness of the first epidermis layer (Δ㎛) was 17㎛.

In particular, in the composition for spray coating of Comparative Example 3, the solid content having an average particle diameter of 0.1 μm has a volume ratio of 0.1% to the total solid content, the volume ratio of the solid content having an average particle diameter of 0.1-1.0 μm is 20.5%, and the average particle diameter is 1- The volume ratio of the solid content of 5 μm is 68%, the volume ratio of the solid content with an average particle diameter of 5-10 μm is 5.7%, and the volume ratio of the solid content with an average particle diameter of 10-20 μm is 5.6%, and the particle size distribution is narrow. It was confirmed that the performance was lowered (see FIGS. 4a and 4b).

In addition, in the composition for spray coating of Comparative Example 4, the spraying processability was lowered, so that the spraying was not good, so it was impossible to measure the in-mold coating property.

On the other hand, in Reference Example 1, the back surface of the skin material became uneven as the powder slush molding moldability was lowered by using the powder containing calcium carbonate. There was a problem of this deterioration.

1: Skin material for automobile interior materials
100: first epidermal layer 200: second epidermal layer

Claims (15)

From top to bottom, the first epidermal layer 100; and a second epidermal layer 200 having a color different from that of the first epidermal layer; As a skin material for automobile interior materials comprising:
The first skin layer 100 includes a filler,
In the car interior material 1, the average value of the color difference (ΔE) between the reference point and any five points is 0.5 or less (CIELAB (1976) color space, D65 light source, SCI measurement method) Skin material for automobile interior materials.
According to claim 1,
The skin material for an automobile interior material has an average value of the thickness deviation (Δ㎛) of the first skin layer 100 is 15㎛ or less.
According to claim 1,
The first skin layer (100) is a skin material for an automobile interior material that is partially formed on the upper portion of the second skin layer (200).
According to claim 1,
The second skin layer 200 is a skin material for an automobile interior material that does not contain a filler.
After positioning the masking jig at a predetermined position in the mold, a first skin layer forming step (S1) of forming a first skin layer by spray-coating a spray coating composition containing a filler (S1); and
a second skin layer forming step (S3) of forming a second skin layer under the first skin layer through a powder slush molding process using powder for powder slush molding; A method for manufacturing a skin material for automobile interior materials comprising:
In the car interior material, the average value of the color difference (ΔE) between the reference point and any five points is 0.5 or less (CIELAB (1976) color space, D65 light source, SCI measurement method) A method for manufacturing a skin material for automobile interior materials.
6. The method of claim 5,
The spray coating composition comprises 100 parts by weight of a polyvinyl chloride resin (a), 61-95 parts by weight of a plasticizer (b), and 2.5-20 parts by weight of a filler (c).
7. The method of claim 6,
_{The polyvinyl chloride resin (a) is a paste polyvinyl chloride resin (a 1} ) having an average particle diameter of 0.1-3 μm and a straight polyvinyl chloride resin having an average particle diameter of 15-40 _{μm (a 2} ) A 60-90: A method of manufacturing a skin material for automobile interior materials, which is mixed in a weight ratio of 10-40.
7. The method of claim 6,
The filler (c) has an average particle diameter of 0.03 μm to 0.85 μm.
7. The method of claim 6,
The composition for spray coating has a viscosity of 6,000-20,000cps under the conditions of 21-26°C and 1-5rpm.
10. The method of claim 9,
The composition for spray coating has a viscosity of 500-3,000cps under the conditions of 21-26°C and 18-25rpm.
7. The method of claim 6,
The composition for spray coating has a thixotropy index of 3-15.
7. The method of claim 6,
The composition for spray coating is continuously distributed in the range of 0.09-20.9 μm in average particle diameter.
7. The method of claim 6,
The composition for spray coating has an average particle diameter of 0.09-0.1 μm, and the volume ratio of the solid content to the total solid content is 1.0-3.0%.
14. The method of claim 13,
The composition for spray coating has an average particle diameter of 10.0-20.0 μm and a volume ratio of 0.5 to 5% of solids with respect to total solids.
6. The method of claim 5,
The powder for powder slush molding includes a core; and a core-shell structure polyvinyl chloride powder comprising a particle unit including a shell surrounding the core surface,
The core contains 50-120 parts by weight of a plasticizer based on 100 parts by weight of the straight polyvinyl chloride resin, and the shell contains 3-20 parts by weight of the paste polyvinyl chloride resin.

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