JPH02269041A - Rubber molded product with finish film layer - Google Patents

Abstract

PURPOSE:To directly form a heated gelled layer of PVC paste on a molded product main body in a good adhesion state by interposing an adhesive layer composed of a specific blend polymer or a rubber compound thereof between the molded product main body and a finish film layer. CONSTITUTION:An adhesive layer 5 composed of a blend polymer formed by adding 5-20 pts.wt. of at least one of a styrenic polymer and polyalkenemer to 100 pts.wt. of a mixture of nitrile rubber (NBR)/ethylene propylene rubber (EPDM) (wt. ratio)=80/20-40/60 or a rubber compound thereof is interposed between a molded product main body 1 and a finish film layer 3. By this method, a rubber molded product with finish film layer good in the adhesion of the rubber molded product main body and the finish film layer formed from a gelled layer of PVC paste can be obtained without performing pretreatment requiring a number of processes.

Description

DETAILED DESCRIPTION OF THE INVENTION Industrial Field of Application The present invention relates to a rubber molded article in which a finish coating layer is formed of a gelled layer of pvC paste on a molded article body made of EPDM.

Examples of products to which the rubber molded product with a finish coating layer of the present invention can be applied include window weather strips (Figure 1), glass weather strips (Figure 2), and side moldings (Figure 3). A list of polymer/plasticizer abbreviations used herein is shown below.

N B R--Nitrile rubber, E P D M-- Ethylene propylene rubber (sulfur vulcanizable type), P V C-- Polyvinyl chloride, P P-- Polypropylene, ABS-- Acrylonitrile -Butadiene-styrene resin, SBS...Styrene-butadiene-styrene block copolymer DOP-...Dioctyl phthalate.

<Prior Art> Here, explanation will be given using a window weather strip for an automobile as an example, but the invention is not limited to this.

The main bodies of weather strips used in automobiles are usually made of ethylene propylene rubber from the viewpoint of weather resistance, ozone resistance, heat resistance, etc.In addition, due to the increasing demand for improved design in automobiles these days, The appearance of a weather strip with a vivid and deep black or chromatic color design is eagerly awaited.

However, it has been difficult to obtain a vivid and deep black or chromatic color on the molded surface of a rubber molded product due to the characteristics of the rubber material itself.

Therefore, as a result of the inventor's earnest efforts in development,
Vibrant coloring is easy and a thick coating layer (approximately 50
We came up with the idea of forming a finishing coating layer with a gelled layer of PvC paste, which can be easily formed (micrometer or larger), has good weather resistance, and can easily adjust its rigidity and hardness (Patent Application No. 1983-
Reference No. 334550334551 (unpublished at the time of filing).

<Problems to be Solved by the Invention> However, when the molded product body is made of EPDM, it is difficult to form a heat-gelled layer of PVC paste with good adhesion directly on the molded product body. Therefore, as pre-treatment, it is necessary to perform puff treatment, primer treatment, etc. on the surface of the vulcanized rubber. These pretreatments require many man-hours.

In view of the above, the present invention provides a finish coating film that has good adhesion between the rubber molded product body and the finish coating layer formed of a gelled layer of PVC paste without the need for pre-treatment that requires a lot of man-hours. The purpose is to provide layered rubber molded products.

Means for Solving the Problem> Finishing of the present invention! ! ! The membrane-coated rubber molded product has the following configuration to solve the above problems.

In a rubber molded product in which a finish coating layer is formed with a gelled layer of PVC paste on an EPDM molded product body, NBR/EPD is applied between the molded product body and the finish coating layer.
M (weight ratio) - 80/20 to 40/60 mixture 100
At least one type of styrenic polymer polyalkenamer is contained in 5 to 20 parts by weight! It is characterized in that an adhesive layer consisting of a blended polymer or a rubber compound thereof added in a certain amount is interposed therebetween.

Detailed explanation of the method The means of the present invention will be explained in detail below.

In addition, in the following explanation, "r parts" indicating the compounding unit is "parts by weight".
means.

1 to 3 show rubber molded products to which the present invention can be applied,
Fig. 1 is a sectional view of the window weather strip, Fig. 42 is a sectional view of the glass weather strip, and Fig. 3 is a sectional view of the side molding.

(1) The molded product main body 1 is made of EPDM.

Here, EPDM refers to ethylene, propylene, ethylidene norbornene, cyclopentadiene as a third component,
1. Adding a small amount of non-conjugated diene such as 4-hexadiene,
It is copolymerized to introduce double bonds into the side chains, making it sulfur vulcanizable. The polymer usually contains a reinforcing filler (carbon black or white carbon),
Add auxiliary materials such as plasticizers, lubricants, and vulcanizing agents. 1st
The table shows the formulation of the EPDM rubber compound that can be used in this example.

(2) Then, on the designed surface of the molded product body 1, a finishing coating layer 3 is formed of a gelled layer of PvC paste.

Here, PVC paste is plastisol or organosol made into a paste by dispersing fine paste resin with a particle size of several μm or less in a plasticizer or a dispersion medium containing a plasticizer and a diluent. After forming, it is gelled (hardened) by heating and melting, and when used as a paint, there is no weight change due to the film forming operation compared to solvent-based paints (100% solid content concentration). The amount of adhesion after , - times of coating is large, and furthermore, there is almost no fire or hygiene hazard ("Plastic Processing Technology Handbook" Nikkan Kogyo Shimbun Sha Series, published December 20, 1978, No. 485-
(see page 48G) and this PvC paste usually contains stabilizers, carbon black or colorants (pigments, dyes).
Mix auxiliary materials such as

(3) In the present invention, an adhesive layer (glue line) 5 made of the following blended polymer or a rubber compound thereof is interposed between the molded article body 1 and the finish coating layer 3.

rNBR/EPDM (weight ratio) irises 80/20 to 40/6
A blend polymer in which 5 to 20 parts by weight of at least one of a styrene polymer and a polyalkenamer is added to 100 parts by weight of a mixture of
This is a part of those disclosed in Japanese Patent No. 3341, and those prepared by emulsion polymerization are usually used.

■The above NBR may be a general-purpose one, but ΔTg-63~
It is desirable to meet the requirements of 90°C and a bound nitrile content of -10 to 50% (see JP-A-61-53340).
.

■In NBR/EPDM, if NBR is excessive,
EPDM has poor adhesion to the molded product body and ozone resistance.
If it is excessive, the finish coating layer (PvC paste layer) 7
This may cause problems in adhesion.

(2) Examples of the styrene polymer include ABSSBS, and examples of the polyalkenamer include transpolybentenamer and transpolyoctenamer.

(2) The above blended polymer usually contains auxiliary materials such as a reinforcing filler (carbon black or white carbon), a plasticizer, a lubricant, a vulcanizing agent, and, if necessary, a coloring agent. Tables 3 and 4 show the formulations of the carbon black compound system and the white filler compound system (for colored rubber), respectively.However,
When the thickness of the adhesive layer is less than 0.5cm,
In cases where the migration of auxiliary materials such as vulcanizing agents from the solid rubber portion 3 can be expected, it is not inevitable.

(2) The thickness of the adhesive layer is 0.1 to 2 (2).

If the groove is less than 0.11, it is difficult to notice the effect of the adhesive layer, and if it exceeds 2, the material cost increases and the properties of the molded product body are lost, which is not desirable.

(4) Methods for manufacturing the rubber molded product of the present invention include the following methods.

(2) Co-extrude the molded product body (weather strip body) 1 and adhesive layer 5 using each material. Note that the adhesive layer 5
The chisel may be formed by other coating methods such as knife coating, or the main body of the molded product may be prepared by molding such as injection-transfer compression, and the adhesive layer may be coated from adhesive, thin sheet, etc. - It may be formed by means such as pressing.

(2) Subsequently, after heating and vulcanizing the molded product body 1 and the adhesive layer 5, a PVC paste is applied to the designed surface of the molded product body 1 and gelled by heating to form the finish coating layer 3.

Among the general-purpose coating methods, flow coating, brush coating, roller coating, dipping coating, spray coating, etc. can be used to apply the above PVC paste, but the application surface may have an uneven shape. If the surface is easily deformed or deformed, flow painting is recommended.

The amount of coating at this time depends on the required design! !
! The coating amount is such that the film thickness is 50 to 2000 μm.
Finishing after heating and gelling! ! ! The film thickness of the film layer is 50 to 2000 μm, which is almost the same as the coating film thickness before gelation.

The heating gelation process of this PvC paste is carried out in the molded product body 1.
This may be carried out after the completion of vulcanization of the adhesive layer 5, but from the standpoint of thermal efficiency and productivity, the molded product body 1 and the adhesive layer 5
It is desirable to have this function also in the vulcanization process (EPD
The vulcanization conditions for the M-based rubber and the heating gelling conditions for the PvC paste may be open (temporally open). It becomes possible to perform each step of sulfurization or heat gelation continuously. That is, after the molded product body 1, adhesive layer 5, and finish coating layer 3 are continuously extruded or applied, the molded product may be transferred to a vulcanization (heat gelling) step.

<Actions and Effects of the Invention> The rubber molded product with a finish coating layer of the present invention has the above-mentioned
In a rubber molded product in which a finish coating layer is formed with a PVC-based gel layer on a PDM molded product body,
Between the molded product body and the finish coating layer, NBR/EPDM
(Weight ratio) -80/20 to 407130 mixture 100
part, at least 5 to 20 parts of a styrene polymer or a polyalkenamer is added to the NBR.
/E Because it has a structure in which an adhesive layer made of PDM blend polymer or its rubber compound is interposed, it has the following functions and effects.

The finished rubber molded product of the present invention includes a molded product body,
Conventionally, in order to obtain good adhesion between the finished coating layer formed of the gelled layer of PvC paste, pre-treatments that require a lot of man-hours, such as puff treatment and primer treatment, have been required.

In contrast, the rubber molded product with a finish coating of the present invention can be molded simply by interposing an adhesive layer with a specific polymer rubber or its rubber compound, without the need for such a time-consuming pretreatment. Good adhesion can be ensured between the product body and the finish coating layer. Therefore, it is possible to manufacture a rubber molded article having a finishing coating layer made of a heat-gelled layer of PvC paste with good productivity.

<Examples> Examples conducted to confirm the effects of the present invention will be described below.

Example ■: Crosshead type extruder (specification cylinder diameter 60 mm
, compression ratio! , 5), the adhesive layer 5 (
The molded product body (weather strip) 1 whose design surface was covered with adhesive layer thickness: 0.4■■) was extruded (conditions: extrusion speed 5 m/min), and then the extruded product (molded product body) 1, a PvC paste (after vacuum defoaming) having the formulation shown in Table 4 was applied to a film thickness of 100 μm using a shower coating method to form a finishing coating layer (PVC paste layer) 3. The extrudate was carried into a hot air tank, and the paste layer was simultaneously heated and gelled in the vulcanization pot of the molded article body 1 and the adhesive layer 5 under the conditions of 200° C.×10 min.

Example ■: In the above Example ■, after extruding the molded product main body 1, the molded product main body 1 is carried into a hot air tank, and the molded product main body 1 and the adhesive layer 5 are vulcanized under the conditions of 220° C. x 5 minutes. After performing Pv
Paste C was formed in the same manner as above and heated to gel under the same conditions.

After allowing 24 hours at room temperature for Example 1 thus prepared, the adhesive strength between the finish coating layer 7 and the weatherstrip main body 1 was determined by a 180'' peel test (tensile speed: 10
cm/min), the peel strength was 5.2k.
g/c■, ■4.5kg/c■ (rubber base material destroyed in both cases).The finished coating films were all bright and deep black.

Table 1 (Unit double placement part) *Japanese synthetic rubber - Manufacturing table (Unit: parts by weight) Table (Unit: parts by weight) (NBR/EPDM ■) 0/3 Table * Manufactured by Sumitomo Chemical ■

[Brief explanation of drawings]

Fig. 1 is a sectional view of a window weather strip which is an example of a molded product to which the present invention can be applied, Fig. 2 is a sectional view of a glass weather strip which is another example, and Fig. 3 is a sectional view of yet another example. It is a sectional view of the side molding shown. 1... Molded product body, 3... Finishing coating layer, 5... Adhesive layer, D... Design surface. Patent applicant: Toyoda Gosei Co., Ltd.

Claims (1)

[Scope of Claims] A rubber molded article in which a finish coating layer is formed of a gelled layer of PVC paste on an EPDM molded article body, wherein between the molded article body and the finish coating layer, NBR/EPDM (weight ratio) = 80/20 to 40/60
Styrenic polymer,
1. A rubber molded article with a finishing coating layer, characterized in that an adhesive layer made of a blended polymer or a rubber compound thereof containing 5 to 20 parts by weight of at least one polyalkenamer is interposed.