JPH04307235A - Molding for vehicle - Google Patents

Abstract

PURPOSE:To obtain a lightweight molding for a vehicle capable of being subjected to top coating good in close adhesiveness without using a primer by forming at least the surface layer of a molding main body composed of a polyolefinic thermoplastic elastomer (TPO) from TPO chemically modified with an unsaturated monomer having a specific functional group. CONSTITUTION:A molding main body 1 is formed from TPO and at least the surface layer part 1b thereof is formed using TPO chemically modified with either one of an unsaturated epoxy monomer, an unsaturated hydroxy monomer, unsaturated carboxylic acid and a polyfunctional monomer having one or more amino group. This chemical modification can be performed by mixing 0.01-10 pts.wts of the abovementioned monomer with 100 pts.wt. of TPO and applying dynamic heat treatment to the resulting mixture in the presence of org. peroxide. The molding main body is pref. constituted of a core part 1a with hardness Hs of 50-98 and a surface layer part 2b with hardness Hs of 90 or more and can be molded by two-color extrusion or injection molding.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle molding whose main body is made of TPO. In particular, the present invention is suitable for vehicle moldings that require lightness and good design, such as protector moldings for automobiles.

[0002] In this specification, the compounding unit is a weight unit unless otherwise specified.

[0003] JI, which is used without explanation in this specification,
Plastic abbreviations specified in S K 6900,
The following is a list of abbreviations based on the rubber nomenclature specified in ASTM D1418.

(i) Abbreviation for plastic PVC...polyvinyl chloride, PP...polypropylene, PE...polyethylene (ii) Abbreviation for rubber EPM...ethylene propylene rubber (binary copolymer system),
EPDM...Ethylene propylene rubber (non-conjugated diene copolymer system), IIR...Butyl rubber,

[0005]

BACKGROUND OF THE INVENTION The above-mentioned moldings are usually mainly made of a soft PVC molding material, which is low cost, has good workability, and can be easily adjusted to the required hardness and flexibility. However, soft PVC has a high specific gravity of 1.16 to 1.45 (see page 1130 of "Chemical Handbook Applied Chemistry Edition II Materials Edition").
This is undesirable from the standpoint of weight reduction. Therefore, thermoplastic elastomer (hereinafter referred to as "TP") was selected as the material for forming the molding body.
It's called "E". ), the specific gravity (density) is the smallest at 0.88 ("Polymer material One point-19
"Elastomers" edited by the Society of Polymer Science and Technology, p. 67), and
It is conceivable to use TPO molding material, which has excellent weather resistance and cold resistance. On the other hand, TPO molded products have poor scratch resistance and are susceptible to deterioration and chalking due to outdoor exposure, so when applied to moldings, it is necessary to paint the molded products.

[0006]

[Problems to be Solved by the Invention] However, since TPO is a non-polar material, general-purpose urethane paints that are normally used to impart scratch resistance, abrasion resistance, etc.
It was believed that direct painting on PO molded products, that is, primerless painting, was not possible.

That is, after the molded product has been released from the mold, the surface of the molded product is cleaned with a chlorinated solvent, and then an undercoating process using a chlorinated polyethylene primer or the like is applied, followed by a general-purpose urethane paint (which has excellent scratch resistance). ) needed to be overcoated.

[0008] In view of the above, an object of the present invention is to make it possible to form a topcoat film on a molding body made of a TPO molding material with a small specific gravity, which has adhesion sufficient for practical use even if it is primerless, and to provide a lightweight, lightweight material. To provide a molding for a vehicle with good productivity.

[0009]

[Means for Solving the Problems] The vehicle molding of the present invention solves the above problems by the following configuration.

[0010] In a vehicle molding comprising a main body part and an insert part, and the main body part is formed of TPO, the TPO contains an unsaturated epoxy monomer, an unsaturated hydroxy monomer, an unsaturated carboxylic acid, and an unsaturated carboxylic acid. A molding for a vehicle, characterized in that it is chemically modified with one or more polyfunctional monomers containing one or more amino groups.

[0011]

[Detailed explanation of means]

Next, each configuration of the above means will be explained in detail.

A. In the molding of the present invention, the molding body 1 is made of polyolefin thermoplastic elastomer (hereinafter referred to as "TPO").
That's what it means. ) is considered to be a higher-level constituent requirement.

(1) Here, the molding body 1 has a core portion 1
a and a surface layer 1b. The hardness of the core 1a is HS (J
IS A) 50 to 98, and it is desirable to design the material so that the hardness of the surface layer portion 1b is HS (JIS A) 90 or higher. The flexibility of the entire molding can be shared by the core part 1a, and the wear resistance and scratch resistance can be shared by the surface layer part 1b, making it easier to design a molding with higher performance. Furthermore, chemically modified TPO, which will be described later, is more expensive than general-purpose TPO.
It is sufficient to form only the surface layer portion 1b with PO, which can reduce the increase in material costs.

In the illustrated example, an insert 3 is buried in order to limit thermal expansion and contraction of the molding. The material of the insert 3 is usually made of steel plate. In this case, in order to ensure the bonding strength with the molding body 1, the insert part 3
A bonding hole is formed in the. However, chemically modified T described below
It is not necessary if the PO has adhesive properties to metals.

Further, double-sided tape 5 is attached to the molding body 1 for convenience of attachment to the vehicle body. The double-sided tape 5 has a support 7 made of polyethylene foam sheet or the like.
It has adhesive layers 9, 9 on both sides, and the adhesive layer 9 on the outer surface side is protected with a release paper 11.

(2) TPO means that the hard segment consists of one or more crystalline polymers selected from PP, ethylene copolymerized PP, and PE, and the soft segment consists of EPM, EPDM, and IIR. It refers to an amorphous material selected from one or more of these. TPO includes both blend type and polymer type.

[0017] The ratio of the hard segment and the soft segment of TPO corresponds to the hardness: former/latter = 3
0/70 to 70/30 (preferably 40/60 to 60/
40). If the ratio of hard segments is too large, it will be difficult to impart flexibility to the elastomer portion, and the hardness will become too high. On the other hand, if the proportion of the soft segment is too large, the physical properties such as strength of the elastomer portion will deteriorate.

[0018] The propylene content of the EPM or EPDM serving as the soft segment is 10 to 40% (preferably 15 to 25%).

(2) When the TPO is of a blend type, it is desirable to use a dynamic vulcanization type soft segment in which the soft segment is partially or completely crosslinked with an organic peroxide during kneading. When the soft segment is partially or completely crosslinked, the oil resistance and heat resistance of the molded product, and
This is because the tensile strength, tear strength, etc. are increased compared to the case where the soft segments are not crosslinked.

(3) In order to use the above TPO as a molding material, the above polymer TPO is usually mixed with a plasticizer (for example, paraffin wax type), an inorganic filler (for example, silica type), and a coloring agent (for example, carbon). It is prepared by mixing and kneading auxiliary materials such as (black) etc. and making it into pellets.

[0021] In terms of physical properties, the molded product has a hardness of the above-mentioned value and a tensile strength (JIS K 6301, TB).
is 100 kgf/cm2 or more (preferably 130 kgf/cm2 or more
Select the type and amount of TPO and other auxiliary materials so that Furthermore, due to injection moldability,
Material flow MFR (ASTM D 1238) 4g/10
TPO and other auxiliary materials are selected so that the heating time is at least 15 g/10 minutes (preferably at least 15 g/10 minutes).

(4) The molding method is carried out by extrusion molding or injection molding. When the molding body 1 is composed of a core portion 1a and a surface layer portion 2a, two-color extrusion molding or two-color injection molding is performed. In the case of extrusion molding, the molding conditions are:
Extrusion material temperature: 180-230℃, in the case of injection molding, injection material temperature 200-240℃, molding pressure 100-200℃
kgf/cm2.

B. The mall of the present invention has the above-mentioned TP
O is any one or two or more monomers of unsaturated epoxy monomers, unsaturated hydroxy monomers, unsaturated carboxylic acids, and polyfunctional monomers containing one or more amino groups A lower component requirement is that it be chemically modified with.

(1) Specifically, Japanese Patent Application Laid-Open No. 64-852
No. 06, JP-A-1-259047/259048/25
TPO described in Publication No. 9049 and the like can be used.

That is, the TPO contains 0.01 to 10 parts of the unsaturated monomer having the above specific functional group per 100 parts of the total amount of the hard segment component (PP etc.) and the soft segment component (EPDM etc.). The soft segment component is partially crosslinked by dynamically heat-treating the blended product in the presence of an organic peroxide.

(2) Next, the functional monomers mentioned above are not particularly limited, but the following examples are preferable.

■Unsaturated epoxy monomer: glycidyl methacrylate (hereinafter abbreviated as "GMA"), glycidyl acrylate.

■Unsaturated hydroxy monomer...Hydroxypropyl methacrylate (hereinafter abbreviated as "HPMA"),
Hydroxyethyl acrylate, hydroxyethyl methacrylate.

■ The unsaturated carboxylic acids mentioned above include maleic acid, bicyclo[2,2,1]hept-2-ene-5,
6-dicarboxylic acids or acid anhydrides thereof are preferred.

■ Examples of the polyfunctional monomer having an amino group include unsaturated amides such as allylamide (hereinafter abbreviated as "AAD"), acrylamide, and methacrylamide; unsaturated amines such as vinylamine and allylamine;
Various amino alcohols, diamines, polyamines, acid amides, hydrazine, and aromatic amines can be used.

C. The molding body molded as described above using the general-purpose TPO molding material and the chemically modified TPO molding material is then painted. That is, after releasing the mold, it is washed with a chlorinated solvent, and then a top coat (usually urethane type) is applied directly without a primer. The coating method is not particularly limited, but may be spray coating or dip coating. Coating film 1 formed on the surface of the mold body 1 manufactured in this way
No. 3 has sufficient coating film peeling strength for practical use, as shown in the examples below, even if it is primerless.

[0032]

[Operations and Effects of the Invention] The vehicle molding according to claim 1 of the present invention has the above-described structure, so that even if it is primerless, it can form a practically usable close contact with the molding body made of TPO material having a small specific gravity. It becomes possible to form a topcoat film with properties. Furthermore, when a double-sided tape serving as a means for attaching the vehicle body is attached to the back surface of the molding body, the adhesion is improved and the material for the adhesive layer of the double-sided tape can be selected from a wider range. Therefore,
A lightweight TPO molding can be manufactured with good productivity.

[0033] Furthermore, the vehicle molding according to claim 2 has a molding main body having a two-layer structure of a core part and a surface part.
It is easy to manufacture moldings that have a good balance between opposing physical properties such as flexibility and wear resistance. Further, it is sufficient to use expensive chemically modified TPO only in the surface layer, thereby suppressing an increase in material costs.

[0034]

[Examples] In order to better understand the present invention, examples will be explained below.

(1) Preparation of TPO molding material: EPDM
: 50 parts, PP: 50 parts, and process oil: 30 parts in a Banbury mixer in a nitrogen atmosphere at 180°C.
After kneading for 5 minutes, the mixture was passed through a roll and a square pellet was prepared using a sheet cutter. To 100 parts of the square pellets, the monomers shown in Table 1 were added together with the indicated amount and 0.3 part of organic peroxide, and the mixture was stirred and mixed in a Henschel mixer, and the mixture was heated in an extruder at 220°C in a nitrogen atmosphere. After extrusion at temperature, the TPO molding material used in this example was prepared by passing it through a pelletizer.

(2) Molding and painting of the molding body Using the TPO molding material prepared as described above, a molding body (excluding the coating film) having the shape shown in FIG. 1 was two-color extrusion molded. The molding conditions were: effective L/D = 22, die temperature 190
℃, extrusion speed 400 mm/min. The insert 3 was made of steel plate.

[0037] Subsequently, urethane paint ("Soflex 260" manufactured by Kansai Paint Co., Ltd.) was spray-coated on the mold body to a coating thickness of 30 μm.

(3) Physical property tests and evaluation of test results The following physical property tests were conducted on the moldings of each of the above examples and the molded products of each material. The test results are shown in Table 1.

[0039] Paint film adhesion method: After application, after being left at room temperature for 24 hours, a paint film adhesion test (seam peeling test: JISK 5400) was performed on test pieces cut out from three locations on both sides and the top surface of the molding. Ta.

Evaluation: In the example, all parts had an evaluation score of 10 points (0/100), and had coating film adhesion that could withstand practical use.

■Basic physical properties of molded products: Method: According to JIS K 6301, hardness (HS
JIS A), tensile strength (TB), elongation at break (EB
),It was measured.

Evaluation: All of the molding materials used in the present invention have the basic physical properties required for molds.

■Adhesive strength: For each example, the adhesive strength between the insert and the molding body was determined by a 180° peel test (pulling speed 25 mm/m).
in).

Evaluation: Example 4 has higher adhesive strength between the insert and the molding body than the other examples.

[0045]

[Table 1]

[Brief explanation of drawings]

FIG. 1 is a partially sectional perspective view showing an example of a molding to which the present invention is applicable.

[Explanation of symbols]

1 Mall body, 3 Insert, 5 Double-sided tape,

Claims (2)

[Claims] 1. A vehicle molding in which a molding body is formed of a polyolefin thermoplastic elastomer (hereinafter referred to as "TPO"), wherein the TPO forming at least a surface layer portion of the molding body is made of an unsaturated epoxy monomer. mer, unsaturated hydroxy monomer, unsaturated carboxylic acid, and 1
Any one of the polyfunctional monomers containing 1 or more amino groups
A vehicle molding characterized by being chemically modified with a species or two or more monomers. 2. In claim 1, the molding main body consists of a core portion and a surface layer portion, and the hardness of the core portion is HS (JIS A).
) 50 to 98, and the hardness of the surface layer is HS (JIS
A) A molding for a vehicle characterized by having a diameter of 90 or more.