KR20200036309A - A skin material for automobile interior materials and a method for manufacturing the same - Google Patents

Abstract

The present invention relates to a surface material for an automobile interior material and to a method for manufacturing the same. More specifically, the present invention relates to: a surface material for an automobile interior material which can realize weight reduction while preventing damage to the surface on the surface material of the automobile interior material; and a method for manufacturing the same. An objective of the present invention is to provide: the surface material for the automobile interior material which can realize weight reduction while preventing damage to the surface of the surface material; and the method for manufacturing the same. The surface material for the automobile interior material comprises a first skin layer (100) and a second skin layer (200) from top to bottom, and has a specific gravity of 0.6 to 1.1.

Description

A skin material for automobile interior materials and a method for manufacturing the same}

The present invention relates to a surface material for a vehicle interior material and a method for manufacturing the same, and more particularly, to a surface material for a vehicle interior material and a method for manufacturing the same, which can realize light weight while preventing damage to the surface of the surface material for the vehicle interior material.

In general, powder slush molding (Powder Slush Molding) method has a higher design freedom than the conventional vacuum forming method, and has the advantage of realizing the effect of maintaining an embossed pattern.It is mainly applied to the skin material of the instrument panel of high-end automobiles. However, recently, it has been spreading to small and medium-sized vehicles, and the application area is also gradually expanding from the instrument panel to automobile interior parts such as gearboxes and door trims.

On the other hand, as disclosed in Korean Patent Application Publication No. 10-2016-0148107 as a skin material for automobile interior materials, polyvinyl chloride resin (PVC), which is inexpensive and capable of molding in various forms, is mainly used, but the polyvinyl chloride resin The specific gravity was about 1.2, so there was a problem too heavy.

In order to solve this, the inventors of the present invention tried to implement light weight by using a chemical foaming agent such as azodicarbonamide in powder slush molding powder for preparing a skin material, but when the chemical foaming agent is applied to the skin material, There is a problem in that the appearance of the skin material is deteriorated as an open cell occurs and damage to the surface of the skin material occurs.

KR 10-2016-0148107 A (December 26, 2016)

The present invention was devised to solve the above-described problems, and an object thereof is to provide a skin material for automobile interior materials and a method for manufacturing the same, which can realize weight reduction while preventing damage to the surface of the skin material.

In order to achieve the above object,

The present invention provides a skin material for automobile interior materials including a first skin layer and a second skin layer from top to bottom and having a specific gravity of 0.6-1.1.

In addition, the present invention is a first skin layer forming step of forming a first skin layer; And

A second epidermal layer forming step of forming a second epidermal layer under the first epidermal layer; It provides a method for manufacturing a skin material for automobile interior materials having a specific gravity of 0.6-1.1.

The skin material for automobile interior materials of the present invention and a method for manufacturing the same have the effect of satisfying the physical properties required as a skin material for existing automobile interior materials while preventing the damage to the surface of the skin material, while having excellent appearance and light weight. have.

1 is a cross-sectional view schematically showing a skin material for automobile interior materials of the present invention.

Hereinafter, the present invention will be described in detail with the accompanying drawings.

Referring to FIG. 1, the present invention relates to a skin material 1 for automobile interior materials including a first skin layer 100 and a second skin layer 200 from top to bottom, and having a specific gravity of 0.6-1.1.

Specifically, the inventors of the present invention tried to implement a lighter weight of the skin material by including a chemical foaming agent in the powder for powder slush molding used when manufacturing the skin material for automobile interior materials, but damage to the surface of the skin material due to open cells There was a problem that the appearance of the skin material is lowered.

Accordingly, the present invention is to form a skin material for automobile interior materials as a two-layer skin layer as described above, but includes a chemical foaming agent only in the second skin layer 200 located at the bottom, and the first skin layer 100 located at the top is second. It acts as a protective film of the epidermal layer 200, thereby preventing damage to the surface of the epidermal material 1, while reducing the weight.

The specific gravity of the skin material 1 for automobile interior materials of the present invention may be 0.6-1.1, 0.7-1.0 or 0.75-0.9, and if it is less than the above range, properties such as tensile strength and tear strength required as a skin material for automobile interior materials This may be lowered, and if it exceeds the above range, it may have a specific gravity within the above range as it is not possible to realize weight reduction compared to the specific gravity of the conventional polyvinyl chloride resin.

The specific gravity was measured using a digital electronic hydrometer (ALFA MIRAGE, MD300S).

In addition, the skin material for automobile interior materials (1) of the present invention may have a tensile strength of 80kgf / cm ² or more, or 81kgf / cm ² or more, and can satisfy the tensile strength required as an existing skin material for automobile interior materials within the above range. It has excellent mechanical properties.

The upper limit of the tensile strength of the skin material include, but not limiting, one example can be not more than 300kgf / cm ² or below 290kgf / cm ^2.

The tensile strength can be measured using a Universal Testing Machine (Instron, 5960) according to ISO 5207-3.

In addition, the car interior material for the interior material of the present invention (1) may have a breaking elongation of 250% or more or 252% or more, and within the above range, it is possible to satisfy the elongation at break required as an existing surface material for an automobile interior material. It has an excellent effect.

The upper limit of the elongation at break of the skin material is not limited, but may be, for example, 400% or less or 390% or less.

The elongation at break can be measured using an extensometer (Instron, 2603) according to ISO 5207-3.

In addition, the skin material for automobile interior materials (1) of the present invention may have a tear strength of 3 kgf or more or 3.1 kgf or more, and within the above range, the tear strength required as an existing skin material for automobile interior materials can be satisfied, and thus mechanical properties. This has an excellent effect.

The upper limit of the tear strength of the skin material is not limited, but may be, for example, 10 kgf or less or 8 kgf or less.

The tear strength can be measured using a Universal Testing Machine (Instron, 5960) according to ISO 5207-3.

Hereinafter, each layer constituting the skin material for automobile interior materials 1 of the present invention, which can implement lightweight while preventing damage to the surface of the skin material, will be described in more detail.

First epidermal layer (100)

The first skin layer 100 of the present invention is located at the outermost part of the skin material for automobile interior materials, and serves to prevent damage to the surface of the skin material and to realize excellent sensitivity.

Specifically, the first skin layer 100 may include 30-100 parts by weight of a plasticizer and 1-15 parts by weight of an additive with respect to 100 parts by weight of the polyvinyl chloride resin.

More specifically, the first epidermal layer 100 uses a first epidermal layer composition in a sol state containing 30-100 parts by weight of a plasticizer and 1-15 parts by weight of an additive relative to 100 parts by weight of a polyvinyl chloride resin. Can be formed.

The polyvinyl chloride resin included in the first epidermal layer 100 of the present invention may be a resin having flow characteristics of pseudoplastic, which decreases in viscosity as the shear rate increases.

Specifically, the first epidermal layer 100 of the present invention is formed by applying the first epidermal layer composition to a mold and then gelling, in particular, shearing when applied to the mold by using polyvinyl chloride resin having the flow characteristics of the water plastic. Since the speed is high, the viscosity is low and the coating property is excellent, and after application to the mold is completed, the shear rate is low, so the viscosity is increased and the adhesion to the mold is excellent, so the processability is excellent.

More specifically, the polyvinyl chloride resin having the flow characteristics of the pseudoplastic has a viscosity of 10-1000 Pa · s or 100-800 Pa · s at a shear rate of 0.1 (1 / s), and a shear rate of 1000 (1 / It may be 2-9Pa · s or 3-8Pa · s in s), and has excellent coating property within the above range and excellent adhesion to the mold.

 The viscosity of the 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 the same amount for 1 hour.

In addition, the degree of polymerization of the polyvinyl chloride resin is not limited, but may be, for example, 700-1700 or 900-1500.

The polymerization degree was measured in accordance with ASTM D1243 at a temperature condition of 25-32 ° C.

The plasticizer is intended to plasticize the polyvinyl chloride resin to facilitate the coating of the first skin layer composition on a mold, a phthalate plasticizer, a terephthalate plasticizer, a benzoate plasticizer, a citrate plasticizer, and a glycol plasticizer. , Trimellitate-based plasticizer, phosphate-based plasticizer, adipate-based plasticizer, and epoxy-based plasticizer.

Examples of the phthalate plasticizer include 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 plasticizer may be, for example, dioctyl terephthalate, but is not limited thereto.

The benzoate plasticizer is, for example, 2- (2- (2-phenylcarbonyloxyethoxy) ethoxy) ethyl benzoate, glyceryl tribenzoate, trimethylolpropane tribenzoate, isononyl benzoate, 1- Methyl-2- (2-phenylcarbonyloxypropoxy) ethyl benzoate, 2, 2, 4-trimethyl-1, 3-pentanediol dibenzoate, n-hexyl benzoate and trimethylol propane tribenzoate can be used. However, it is not limited thereto.

The citrate-based plasticizer may be, for example, one or more selected from the group consisting of acetyl tributyl citrate, tributyl citrate, acetyl triethylhexyl citrate and triethylhexyl citrate, but is not limited thereto.

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

The trimellitate plasticizer may be, for example, one or more selected from the group consisting of triisobutyl trimellitate, trinormal octyl trimellitate, trioctyl trimellitate and triisononyl trimellitate, but is not limited thereto. no.

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

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

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

In the present invention, as a specific example of the plasticizer, it is eco-friendly, and has excellent thermal stability, and can be used by mixing a trimellitate-based plasticizer capable of improving the plasticizer's migration resistance and an epoxy-based plasticizer having excellent heat resistance.

The plasticizer may be used in 30-100 parts by weight or 50-90 parts by weight with respect to 100 parts by weight of the polyvinyl chloride resin. If it is less than the above range, the viscosity of the first epidermal layer composition may increase, and coating properties may be deteriorated in the mold, and if it exceeds the above range, the gelling property after coating may decrease, and plasticizer migration may occur, and thus can be used within the above range.

The additive may be at least one selected from the group consisting of a heat stabilizer and a light stabilizer, the content of which can be used 1-15 parts by weight or 5-10 parts by weight relative to 100 parts by weight of the polyvinyl chloride resin. If it is less than the above range, it cannot satisfy the light stability or heat stability required as a skin material for automobile interior materials, and when it exceeds the above range, a stabilizer may be transferred to the surface of the skin material during long-term aging, resulting in deterioration in appearance quality. Can be used within the range.

In addition, the first skin layer 100 of the present invention may optionally further include other additives, the other additives consisting of a release agent, antioxidant, antifoaming agent, leveling agent, antistatic agent, dispersant, flame retardant, pigment and adhesion promoter It may be one or more from the group.

The other additives can be used in the conventional types used in the art, the present invention does not particularly limit the type and content.

The viscosity of the first epidermal layer composition may be 5,000-10,000 cps or 7,000-9,000 cps at conditions of 21-26 ° C., 1-5 rpm, and 25 ° C. and 2 rpm in one embodiment. This has an excellent effect.

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

The first epidermal layer 100 of the present invention may have a thickness of 0.1-0.4mm or 0.2-0.3mm, and if it is less than the above range, it is too thin to prevent damage to the surface of the epidermis and thus the open cell of the second epidermal layer 200 It may be exposed to the surface of the skin material and deteriorate in appearance and sensibility. If the thickness exceeds the above range, the thickness of the second skin layer 200, which will be described later, becomes thinner, so that the specific gravity increases, so that weight reduction cannot be realized, so the thickness within the above range may be obtained. You can.

Second epidermal layer (200)

The second skin layer 200 of the present invention serves to realize the weight reduction of the skin material 1 for automobile interior materials, and may be formed through a powder slush molding process using powder for powder slush molding.

The powder for powder slush molding is a core; And a core-shell structured polyvinyl chloride powder including particle units including a shell surrounding the core surface.

Specifically, the core may include 50-120 parts by weight of a plasticizer, and 0.1-5 parts by weight of a chemical blowing agent with respect to 100 parts by weight of a straight polyvinyl chloride resin, and the shell may include 3-20 parts by weight of a paste polyvinyl chloride resin. have.

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

(A) Core

(A-1) Straight polyvinyl chloride resin

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

The straight polyvinyl chloride resin may have a polymerization degree of 700-2500 or 1000-2000. If it is less than the above range, mechanical properties such as elongation at break and tear strength of the surface material for automobile interior materials may be deteriorated, and if it exceeds the above range, the molding temperature may increase and the moldability of the skin material during the powder slush molding process may decrease. It may have a polymerization degree within the above range.

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

In addition, the pores of the straight polyvinyl chloride resin may be 25-50% or 30-40%. If it is less than the above range, the oil absorption amount of the plasticizer in the straight polyvinyl chloride resin decreases, and if it exceeds the above range, the straight polyvinyl chloride resin may be difficult to manufacture, and thus may have voids in 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 indicate the amount of the plasticizer absorbed by the polyvinyl chloride resin at 20 ° C as a weight percent relative to the polyvinyl chloride resin before absorbing the plasticizer.

(A-2) Plasticizer

The type of plasticizer included in the core is the same as the plasticizer included in the first skin layer 100 described above, so duplicate descriptions will be omitted.

The plasticizer may be used in 50-120 parts by weight or 60-100 parts by weight with respect to 100 parts by weight of the straight polyvinyl chloride resin (A-1). If it is less than the above range, it is not possible to impart sufficient flexibility to the straight polyvinyl chloride resin, and when it exceeds the above range, physical properties of the skin material for automobile interior materials and migration of plasticizers may occur, so it can be used within the above range.

(A-3) Chemical blowing agent

The type of the chemical blowing agent included in the core is not limited as long as it can be used for the straight polyvinyl chloride resin, but specifically, azodicarbonamide, p, p'-oxybisbenzenesulfonyl high Group consisting of p, p'-oxybisbenzene sulfonyl hydrazide, p-toluene sulfonyl hydrazide, sodium bicarbonate and benzene sulfonyl hydarazide It may be one or more selected from.

The chemical blowing agent may be used to decompose at 160-230 ° C. to generate a gas amount of 200-300 ml / gr. If it is less than the above temperature range, it may be difficult to implement a sufficient foaming effect by being pre-foamed during the polyvinyl chloride powder manufacturing process, and when it exceeds the above temperature range, the foaming agent does not decompose and thus it is not possible to impart light weight to the skin material and thus the temperature Chemical blowing agents that decompose within the range can be used.

The chemical blowing agent may be used in an amount of 0.1-5 parts by weight or 0.5-3 parts by weight based on 100 parts by weight of the straight polyvinyl chloride resin. If it is less than the above range, the foaming effect is insignificant to impart light weight to the skin material, and if it exceeds the above range, the thickness of the skin material is not easily controlled during powder slush molding, and the mechanical properties of the skin material may be deteriorated. It can be included within the scope.

The core 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 flame retardant, and an antistatic agent. In the invention, the type and content are not particularly limited.

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

(B) Shell

The shell wraps the core described above to prevent entanglement between particles and plays an important role in the powder slush molding process in the future.

(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 or 800-1400. If it is less than the above range, mechanical properties such as elongation at break and tear strength of the skin material for automobile interior materials may be deteriorated, and if it exceeds the above range, the processability of powder slush molding may be deteriorated to have a polymerization degree within the above range.

In addition, the particle size of the paste polyvinyl chloride resin may be 0.1-20 μm, or 0.3-10 μm. If it is less than the above range, it is preferable to have a particle size within the above range, since the polyvinyl chloride powder has poor flowability, which is difficult for the powder slush molding process, and if it exceeds the above range, it is dispersed in a form that does not cover the core surface.

In addition, the paste polyvinyl chloride resin may be used in 3-20 parts by weight or 5-15 parts by weight relative to 100 parts by weight of the polyvinyl chloride resin included in the core. If it is less than the above range, the polyvinyl chloride core-shell structure is difficult to form, so the flowability of the powder is lowered, which makes the molding process difficult. If it exceeds the above range, the plasticizer is compared to the total resin by the amount of the increased polyvinyl chloride resin. Since the content of is reduced and the physical properties of the skin material is reduced, it can be used within the above range.

The shell may be formed to a thickness of 0.1-20㎛ or 0.5-10㎛. When the thickness of the shell is less than the above range, the flowability of the polyvinyl chloride powder may decrease, and when the thickness of the shell exceeds the above range, formability decreases, so it is preferable to form a thickness within the above range.

The particle size of the polyvinyl chloride powder for powder slush molding may be 100-350 μm or 150-250 μm. If it is less than the above range, the flowability of the polyvinyl chloride powder is poor, which makes it difficult for the powder slush molding process, and when it exceeds the above range, the polyvinyl chloride powder is difficult to melt in a short time, so the powder slush molding processability is lowered, so particles within the range It can have a size.

The polyvinyl chloride powder for powder slush molding comprises: (a) mixing 50-120 parts by weight of a plasticizer and 0.1-5 parts by weight of a chemical blowing agent with respect to 100 parts by weight of a straight polyvinyl chloride resin to form a core;

(b) forming a shell surrounding the surface of the core by putting the core of (a) and 3-20 parts by weight of a paste polyvinyl chloride resin into a cooling mixer;

Hereinafter, each step will be described in detail.

(a) Core formation step

Since the straight polyvinyl chloride resin, plasticizer, and chemical blowing agent included in the core are the same as described above, redundant substrates will be omitted.

In addition, the mixing in the step (a) can be carried out for 60-120 minutes without heating in a Henschel mixer, and in this case, the powder production step is reduced compared to putting it in a Banbari mixer and performing mixing, resulting in excellent production yield. have.

At this time, the mixture of the straight polyvinyl chloride resin, the plasticizer, and the chemical foaming agent included in the core may increase in temperature to about 120 ° C due to frictional heat, and mixing is performed during the time to provide the straight poly through sufficient blending. It is possible to increase the oil absorption amount of the plasticizer in the vinyl chloride resin.

In addition, step (a) may optionally further include one or more additives selected from the group consisting of heat stabilizers, lubricants, antioxidants, light stabilizers, heat resistant agents, flame retardants and antistatic agents.

(b) shell formation step

In the shell forming step, the core prepared in the step (a) is put into a cooling mixer together with an emulsion paste polyvinyl chloride resin and then shaked to form a shell surrounding the core surface to form a core-shell structured poly. It may be a step of preparing a vinyl chloride powder.

The second skin layer 100 of the present invention formed through the powder slush molding process using the powder for powder slush molding described above may have a thickness of 0.5-1.0mm or 0.6-0.8mm, and is relatively less than the above range As the thickness of the first epidermal layer becomes thicker, the specific gravity increases, making it difficult to realize light weight. If it exceeds the above range, the thickness of the first epidermal layer 100 becomes relatively thin, preventing damage to the surface of the epidermal material, resulting in an open cell. Appearance and sensibility may be lowered, and thus may have a thickness within the above range.

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

In addition, the present invention is a first skin layer forming step (S1) of forming a first skin layer; And

A second skin layer forming step (S3) of forming a second skin layer under the first skin layer; It relates to a method for manufacturing a skin material for automobile interior materials having a specific gravity of 0.6-1.1.

Hereinafter, each step will be described in detail.

First epidermal layer forming step (S1)

The first skin layer forming step (S1) may be a step of forming the first skin layer 100 by applying a first skin layer composition to a mold for powder slush molding and gelling.

The first skin layer composition may be prepared by putting each composition described above into a mixer and kneading at room temperature.

The viscosity of the first epidermal layer composition may be 5,000-10,000 cps or 7,000-9,000 cps at conditions of 21-26 ° C., 1-5 rpm, and 25 ° C. and 2 rpm in one embodiment. This has an excellent effect.

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

The coating method may be a spray coating, a knife coating, a comma coating, or a gravure coating method, and a spray coating may be used as a specific embodiment of the present invention.

In order to form the second epidermal layer 200 in the second epidermal layer forming step (S3) described below, the gelling is performed by applying a mold for powder slush molding coated with the first epidermal layer composition at about 200-250 ° C or 210-240 ° C. It can be carried out while heating to.

Forming the second skin layer (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.

The powder slush molding powder is the same as the polyvinyl chloride powder described above, so the overlapping substrate will be omitted.

Specifically, first, the mold for powder slush molding, to which the composition for forming the first skin layer is applied, is heated to about 200-250 ° C or 210-240 ° C. At this time, the composition for forming the first skin layer is gelled to form the first skin layer ( 100) may be formed.

Subsequently, the sealed mold is formed by combining the heated mold with an open container (powder box) loaded with the polyvinyl chloride powder, and then rotating it to form a second skin layer 200 under the first skin layer 100. .

At this time, the chemical blowing agent in the polyvinyl chloride powder may be primary foamed.

Subsequently, after separating the combined mold and the open container (powder box), secondary heating (post-heating) is performed in one case when the polyvinyl chloride powder on the opposite side contacting the first skin layer 100 is less melted and less molded. The chemical blowing agent in the polyvinyl chloride powder is secondarily foamed.

After that, after cooling the mold, the molded material from the mold is demolded from the top to the bottom, including the first skin layer 100 and the second skin layer 200.

The skin material for automobile interior materials of the present invention and a method for manufacturing the same have the effect of realizing light weight while preventing damage to the surface of the skin material.

Hereinafter, a preferred embodiment is provided to help the understanding of the present invention, but the following examples are merely illustrative of the present invention, and it is apparent to those skilled in the art that various changes and modifications are possible within the scope and technical scope of the present invention. It is no wonder that such variations and modifications fall within the scope of the appended claims.

[Example]

Manufacture of skin materials for automobile interior materials

<Example 1>

First epidermal layer forming step (S1)

65 parts by weight of trioctyl trimellitate (TOTM) plasticizer, 100 parts by weight of polyvinyl chloride resin (LG Chemical, PE1311) having flow characteristics of pseudoplastic in a mold for powder slush molding, epoxidized soybean oil (ESO) 5 parts by weight of a plasticizer, 5 parts by weight of a heat stabilizer and 0.2 parts by weight of a light stabilizer were kneaded at room temperature to prepare a first skin layer composition having a viscosity of 8,000 cps (BROOKFIELD AMETEK, DV3T Rheometer, # 63 spindle) at 25 ° C and 2 rpm. To manufacture.

Subsequently, the first skin layer composition was spray-coated on a mold for powder slush molding.

The polyvinyl chloride resin (LG Chemical, PE1311) having the characteristics of pseudoplastic is 500-600 Pa.s at a shear rate of 0.1 (1 / s) and 3.5-5 Pa at a shear rate of 1000 (1 / s). It was .s.

Forming the second skin layer (S3)

83 parts by weight of trioctyl trimellitate (TOTM) plasticizer, 5 parts by weight of epoxidized soybean oil (ESO) plasticizer, 5.5 parts by weight of thermal stabilizer, and 1.2 parts of antioxidant based on 100 parts by weight of straight polyvinyl chloride resin (LG Chemical, LS130) Part, 0.5 parts by weight of light stabilizer and 1.5 parts by weight of chemical foaming agent (Geumyang, CELLCOM-Normal) were placed in a Henschel mixer and mixed for 60-120 minutes without heating to form a core.

Subsequently, 9 parts by weight of the core and paste vinyl chloride resin (LG Chemical, PB1201) were put in a cooling mixer to form a shell surrounding the core surface, thereby forming poly-chloride for powder slush molding in which the particle size of the core-shell structure is 150-250 μm. Vinyl powder was prepared.

Subsequently, the mold for powder slush molding to which the first skin layer composition was applied was heated to 200-250 ° C. At this time, the first skin layer composition was gelled to form a first skin layer having a thickness of 0.25 mm.

Subsequently, the polyvinyl chloride powder for powder slush molding prepared above is loaded in an open container (powder box) to form a closed system by combining the mold and the open container, and then through a powder slush molding process to the bottom of the first skin layer. A second skin layer having a thickness of 0.75 mm was formed.

Subsequently, a first epidermal layer from the mold to the bottom; And it is finished by demolding the surface material for automobile interior materials including a second skin layer.

<Example 2>

In the second skin layer forming step (S3), a skin material for automobile interior materials was prepared in the same manner as in Example 1, except that the content of the chemical blowing agent in the polyvinyl chloride powder for powder slush molding used was 2 parts by weight.

<Comparative Example 1>

Without a first skin layer forming step (S1), a single layer of car interior material having a thickness of 1.0 mm was manufactured through a powder slush molding process using the polyvinyl chloride powder of Example 1.

<Reference Example 1>

The same car as in Example 1, except that the first skin layer composition used polyvinyl chloride resin (LG Chemical, PB1752) that does not have the above properties instead of polyvinyl chloride resin having the flow characteristics of pseudoplastic. A skin material for interior materials was prepared.

The viscosity of the first epidermal layer composition of Reference Example 1 was 550 cps (BROOKFIELD AMETEK, DV3T Rheometer, # 63 spindle) at 25 ° C and 2 rpm.

The polyvinyl chloride resin (LG Chemical, PB1752) that does not have the characteristics of the pseudoplastic is 8-9.5 Pa.s at a shear rate of 0.1 (1 / s) and 4- at a shear rate of 1000 (1 / s). It was 6 Pa.s.

<Reference Example 2>

A skin material for automobile interior materials was prepared in the same manner as in Example 1, except that the thickness of the first skin layer was 0.05 mm and the thickness of the second skin layer was 0.95 mm.

<Reference Example 3>

A skin material for automobile interior materials was prepared in the same manner as in Example 1, except that the thickness of the first skin layer was 0.6 mm and the thickness of the second skin layer was 0.4 mm.

<Reference Example 4>

In the second skin layer forming step (S3), when manufacturing the polyvinyl chloride powder to be used, a skin material for automobile interior materials was prepared in the same manner as in Example 1, except that a chemical foaming agent having a foaming temperature of 120 ° C. was used. .

<Reference Example 5>

In the second skin layer forming step (S3), when manufacturing the polyvinyl chloride powder to be used, a skin material for automobile interior materials was prepared in the same manner as in Example 1, except that a chemical foaming agent having a foaming temperature of 260 ° C was used. .

[Test Example]

Measurement of physical properties of car interior materials

The specific gravity, moldability, appearance, tensile strength, elongation at break, and tear strength of the skin materials for automobile interior materials of Examples 1-2, Comparative Examples 1 and 1-5 prepared above were measured, and the results are shown in the following table. It is shown in 1.

(1) The specific gravity of the skin material was measured using a digital electronic hydrometer (ALFA MIRAGE, MD300S).

(2) The moldability of the skin material was visually confirmed, and ○ if there is no problem of moldability of the front / back of the skin material, and ○ if there is powder that is not completely melted on the front / back of the skin material.

(3) The appearance of the skin material was visually checked for the presence / absence of an open cell, and indicated as X (lower appearance) if there was an open cell, and ○ (excellent appearance) if there was no open cell.

(4) The tensile strength of the skin material was measured using a Universal Testing Machine (Instron, 5960) according to ISO 5207-3.

(5) The elongation at break of the skin material was measured using an extensometer (Instron, 2603) according to ISO 5207-3.

(6) The tear strength of the skin material was measured using a Universal Testing Machine (Instron, 5960) according to ISO 5207-3.

As shown in Table 1, the skin material for automotive interior materials of Examples 1-2 according to the present invention has superior appearance and light weight due to no damage to the surface of the skin material compared to Comparative Example 1, which is a conventional single-layer car interior material. In addition, it was confirmed that all the physical properties such as tensile strength, elongation at break, and tear strength required as a skin material for existing automobile interior materials were satisfied.

On the other hand, the surface material for automobile interior materials of Reference Example 1 prepared using a non-water plastic (pseudoplastic) polyvinyl chloride resin as the first skin layer composition has a low viscosity even after applying the first skin layer composition to the mold and is not well attached to the mold. There was a disadvantage that the moldability was lowered, and accordingly, it was confirmed that the moldability of the first skin layer was lowered and the appearance was lowered.

In addition, the surface material for the automotive interior material of Reference Example 2 in which the thickness of the first skin layer is too thin is damaged due to damage to the surface of the surface material, and the appearance of the first skin layer is too thick. It was confirmed that the thickness of the second skin layer formed by foaming was too thin to increase the specific gravity, resulting in a decrease in weight reduction effect compared to Example 1-2, and difficulty in matching the thin thickness, thereby degrading moldability.

In addition, the surface material for automotive interior materials of Reference Example 4 manufactured using a chemical foaming agent that foams at a lower temperature than Example 1 has little foaming, so that the light weight effect is minimal, and the foaming agent is also pre-foamed to reduce moldability. Compared to Example 1, it was found that the skin material for automobile interior materials of Reference Example 5 prepared using a chemical blowing agent that foams at a higher temperature has a small foaming cell and thus has a light weight effect.

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

Claims (15)

A cover material for automobile interior materials including a first skin layer 100 and a second skin layer 200 from top to bottom, and having a specific gravity of 0.6-1.1. According to claim 1,
The skin material for automobile interior materials has a tensile strength (ISO 5207-3) of 80-300 kgf / cm ² . According to claim 1,
The skin material for automobile interior materials has an elongation at break (ISO 5207-3) of 250-400%. According to claim 1,
The skin material for automobile interior materials has a tear strength (ISO 5207-3) of 3-10 kgf. According to claim 1,
The first skin layer 200 has a thickness of 0.1-0.4mm car interior skin material. According to claim 1,
The second skin layer 100 has a thickness of 0.5-1.0mm car interior material. According to claim 1,
The car interior material is a skin material for automobile interior parts of the instrument panel, console box, arm rest, head rest, filler trim, seat buckle, head liner, glove box, trunk cover trim, airbag cover or steering wheel cover. Skin material for automobile interior materials. A first skin layer forming step (S1) of forming a first skin layer; And
A second skin layer forming step (S3) of forming a second skin layer under the first skin layer; Method of manufacturing a skin material for automobile interior materials having a specific gravity of 0.6-1.1 containing. The method of claim 8,
The first skin layer forming step (S1) is a step of forming a first skin layer by coating a first skin layer composition on a mold for powder slush molding and then gelling to produce a skin material for automotive interior materials. The method of claim 9,
The first skin layer composition is a method of manufacturing a skin material for automobile interior materials comprising 30 to 100 parts by weight of a plasticizer and 1 to 15 parts by weight of an additive relative to 100 parts by weight of a polyvinyl chloride resin. The method of claim 10,
The polyvinyl chloride resin is a resin having flow characteristics of pseudoplastic, and the viscosity is 10-1000 Pa.s at a shear rate of 0.1 (1 / s) and 2-9 Pa. At a shear rate of 1000 (1 / s). Method for manufacturing a skin material for automobile interiors that is s. The method of claim 9,
The viscosity of the first skin layer composition is 21-26 ℃, 5,000-10,000cps at 1-5rpm Method of manufacturing a skin material for automotive interior. The method of claim 8,
The second skin layer forming step (S3) is a step of forming a second skin layer through a powder slush molding process using a powder slush molding powder, a method of manufacturing a skin material for automobile interior materials. The method of claim 13,
The powder for powder slush molding is a core; And a core-shell structured polyvinyl chloride powder comprising a particle unit comprising a shell surrounding the core surface.
The core includes 50-120 parts by weight of a plasticizer and 0.1-5 parts by weight of a chemical foaming agent relative to 100 parts by weight of a straight polyvinyl chloride resin, and the shell includes 3-20 parts by weight of a paste polyvinyl chloride resin. Method of manufacturing a skin material. The method of claim 13,
The powder slush molding process is a method of manufacturing a skin material for automobile interiors that is performed at 200-250 ℃.

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