JPH03240530A - Rubber laminate with finished film layer - Google Patents

Abstract

PURPOSE:To improve the adhesion between a rubber laminate and a finished film layer by interposing a foam-treated rubber compound adhesive layer consisting of a specific composite blend rubber, as a rubber component, between the rubber base material and the finished film layer. CONSTITUTION:In a rubber laminate where a finished film layer 3 is formed with a PVC gelled layer on the rubber base material 1 made of EPDM, between the rubber base material 1 and the finished film layer 3, an adhesive layer is interposed which consists of a foam treated rubber compound having, as a rubber component, the blend rubber of a composite of NBR : 40 - 80wt.%, EPDM : 20 - 60wt.%, and SBR : 0 - 35wt.%. Whereby, an excellent adhesiveness can be insured between the rubber and the finished film layer, and thus a rubber laminate having a finished film layer consisting of the heat-gelled layer of PVC paste can be manufactured with a high productivity.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a rubber laminate comprising an EPDM rubber base, a PvC gelling layer, and a finishing coating layer.

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

NBR... α, β unsaturated nitrile-conjugated diene copolymer rubber represented by nitrile rubber, EPDM...
Ethylene-α-olephy non-conjugated diene copolymer rubber, typified by ethylene propylene diene ternary rubber; SBR: aromatic vinyl compound-conjugated diene copolymer rubber, typified by styrene butadiene rubber. .

pvc...polyvinyl chloride, DOP: Dioctyl phthalate.

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

The main bodies of weather strips used in automobiles and the like are usually made of EPDM from the viewpoint of weather resistance, ozone resistance, heat resistance, etc.

In addition, due to the increasing demand for improved design in automobiles in recent years, it has been eagerly awaited for the appearance of weatherstrips whose design surfaces are bright and deep black or chromatic colors.

However, it has been extremely difficult to obtain a vivid and deep black or chromatic color on the molded surface of the rubber laminate 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 using a gelled layer of PVC paste, which can be easily formed (micrometer or larger), has good weather resistance, and is easy to adjust the rigidity and hardness.
See No. 334550334551 (unpublished at the time of filing).

<Problems to be Solved by the Invention> However, when the rubber substrate is made of EPDM, it is difficult to form a heated gelling layer of PVC paste directly on the rubber substrate with good adhesion. Therefore, as pre-treatment, it is necessary to perform a puff treatment, a brimer 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 layer that has good adhesion between a rubber laminate and a finish coating layer formed of a PVC gelling layer without the need for pretreatment that requires a lot of man-hours. The purpose of the present invention is to provide a rubber laminate.

<Means for Solving the Problems> The rubber laminate with a finishing coat of the present invention solves the above problems by having the following configuration.

In a rubber laminate in which a finish coating layer is formed of a PVC gelling layer on a rubber substrate made of EPDM, 40 to 80% by weight of NBR and E are added between the rubber substrate and the finish coating layer.
PDM: It is characterized by an intervening adhesive layer consisting of a foamed rubber compound whose rubber component is a blended rubber with a composition of 20 to 60% by weight and 0 to 35% by weight of SBR.

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

In addition, in the following explanation, "part J" and "%J" indicating the compounding unit are
Units are by weight unless otherwise specified.

1 to 3 show rubber laminates to which the present invention can be applied,
FIG. 1 is a cross-sectional view of a window weather strip, FIG. 2 is a cross-sectional view of a glass weather strip, and FIG. 3 is a cross-sectional view of a site molding.

(1) The rubber base 1 is made of EPDM.

Here, EPDM refers to ethylene, α-olefin (ex
A small amount of non-conjugated diene such as ethylidenenorbornene, dicyclopentadiene, and 1,4-hexadiene was added as a third component to (propylene) and copolymerized to introduce a double bond into the side chain, making it sulfur vulcanizable. It is something. and,
The polymer is usually blended with additives such as a reinforcing filler (carbon black or white carbon), a plasticizer, a lubricant, a vulcanizing agent, and the like. Table 1 shows the formulation of the EPDM rubber compound that can be used in this example.

(2) Then, on the designed surface of the rubber substrate 1, a finishing coating layer 3, which is a PVC gelling layer, is formed.

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 (100% at solid content concentration), compared to solvent-based paints. -The amount of adhesion after 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, Nos. 485-4)
(See page 86). And this P■C paste usually includes
Auxiliary materials such as stabilizers, carbon black, or coloring agents (pigments, dyes), and, if the PVC gel layer is of a foaming type, a foaming agent is blended in advance.

As the above-mentioned blowing agent, commonly used ones that generate nitrogen gas by thermal decomposition are used, such as dinitrosopentamethylenetetramine (DPT), azodicarboamide (A
DCA), etc. The amount of foaming agent is
The amount is such that the expansion ratio of the PVC gelling layer is 1.5 to 3, and is usually 0.5 to 4 parts per 100 parts of PVC.

When the PVC gel layer is a foamed type, 1, a soft feeling can be easily imparted to the finish coating layer in terms of touch and texture, and it can fully meet the demands of high-end products.

(3) In the present invention, an adhesive layer (glue line) 5 is interposed between the rubber base 1 and the finish coating layer 3, which is made of a foamed rubber compound containing the following blended rubber as a rubber component.

rNBR・40-80%, EPDM: 20-60%
, SBR: 0 to 35%" The blend rubber is the same as that disclosed in JP-A-62-172043, and is usually prepared by an emulsion polymerization method. .

(2) If the NBR is less than 40%, the adhesion to the finish coating layer (PC gel layer) 3 is poor. Also, if it exceeds 80%,
Poor adhesion to the rubber substrate 1 made of EPDM, and poor ozone resistance of the adhesive layer itself ■If EPDM is less than 20%, the ozone resistance of the adhesive layer itself is poor, resulting in EPDM
h) If it exceeds 60%, the finish coating layer (PVC gelling layer)
Adhesion with 3 becomes poor.

(2) If the SBR exceeds 35%, the adhesion to the finish coating layer (PvC gel layer) 3 will deteriorate, and the ozone resistance will also deteriorate. Note that SBR may be 0%, but it is preferable to mix 2% or more because the adhesion to the rubber substrate 1 is improved.

■The above blended rubber contains a foaming agent to make the rubber compound into a foaming formulation, and usually also contains reinforcing fillers (carbon black or white carbon), plasticizers, lubricants, vulcanizing agents, etc. Supplementary materials such as colorants are added by Here, the blowing agent used may be the one used for PVC, but p,p'-oxybis(hensensulfonyl hydrazide) (OBSH) and the like can also be used. In this case, the amount of the foaming agent blended is such that the foaming ratio of the adhesive layer is 1.5 to 3, and is usually 1 to 4 parts per 100 parts of the rubber component.

(2) The thickness of the adhesive layer is 0.2 to 2 mm.

If it is less than 0.2 mm, it will be difficult to perform the adhesive layer's action and, as will be described later, it will be difficult to perform the drug absorption action, and if it exceeds 2 mm,
This is undesirable because it increases the material cost and also causes the properties of the rubber base to be lost.

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

(2) Co-extrude the rubber base (weather strip main body) 1 and adhesive layer 5 using each material. Incidentally, only the adhesive layer 5 may be formed by other coating means such as a knife layer method.

Alternatively, the rubber substrate may be prepared by molding such as injection, transfer, compression, etc., and the adhesive layer may be formed from a co-phase, thin sheet, etc. by means of coating, pressing, etc.

■Subsequently, after heating and vulcanizing the rubber base 1 and adhesive layer 5,
A PVC paste is applied to the designed surface of the rubber substrate 1 and heated (simultaneously foamed) to gel, thereby forming a finish coating layer 3.

Among the general-purpose coating methods, flow coating, brush coating, roller coating, dipping coating, spray coating, etc. can be applied to the application method of the above PVC paste, but if the application surface has 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 set so that the thickness is so~2000 μm.

The thickness of the finished coating layer 3 after heating and gelling is 50 to 2000 μm, which is almost the same as the coating thickness before gelling.

At this time, it is possible to prepare two or more coating devices capable of coating PvC pastes of different colors and coat them in parallel in the extrusion direction or at predetermined lengths on the designed surface of the rubber substrate immediately after extrusion. The finish coating layer can be formed easily and with good productivity. This heat gelling step of the PVC paste may be performed after the completion of vulcanization of the rubber substrate 1 and adhesive layer 5, but from the viewpoint of thermal efficiency and productivity, the heating gelation step of the rubber substrate 1 and adhesive layer 5 is It is desirable to have both functions (the vulcanization conditions for the EPDM rubber and the heat gelling conditions for the PVC base may be time-dependent). In this case, each step of extruding the rubber laminate, covering the adhesive layer, forming the PVC paste layer, and vulcanizing or heating and gelling them can be performed continuously. That is, after the rubber substrate 1, adhesive layer 5, and finish coating layer 3 are continuously extruded or applied, the rubber substrate 1, the adhesive layer 5, and the finish coating layer 3 may be continuously extruded or coated, and then transferred to a vulcanization (heat gelling) step.

<Actions and Effects of the Invention> The rubber laminate with a finish coating layer of the present invention has the above-mentioned (E
In a rubber laminate in which a finish coating layer is formed of a PVc gelled layer on a PDM rubber substrate, 140 to 80% by weight of NBR and EP are added between the rubber substrate and the finish coating layer.
DM: 20~60% by weight, SBR: O~35% by weight
Since the structure includes an adhesive layer made of a foamed rubber compound whose rubber component is a blended rubber having the following composition, the following effects are achieved.

The rubber laminate with a finish coating of the present invention comprises a rubber base and p
Conventionally, in order to obtain good adhesion between the VC gel layer and the finish coating layer, time-consuming pre-treatments such as puff treatment and primer treatment have been required. In contrast,
The rubber laminate with a finish coat of the present invention can be bonded to a rubber base with a finish coat by interposing an adhesive layer with a specific blended rubber or a rubber compound thereof, without such a time-consuming pretreatment. Good adhesion can be ensured between the film layer and the film layer. Therefore, a rubber laminate having a finish coating layer made of a heat-gelled layer of PVC paste can be manufactured with good productivity.

In addition, since the adhesive layer is foamed, the following effects are enhanced.

■When applied to a weather strip or the like and mounted on an actual vehicle, the ability to follow curved parts of the vehicle body is good.

■The migration of vulcanizing chemicals (which have an adverse effect on the PVC gelling layer such as discoloration) from the rubber base to the PVC gelling layer is prevented by the drug absorption effect of the foam adhesive layer, and the PVC
The risk of discoloration of the C gelling layer, that is, the finish coating layer, is reduced.

■Minute irregularities caused by foaming of the adhesive layer affect the surface of the PVC gel layer, making it easy to make the finish coating layer matte.

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

Crosshead type extruder (specification cylinder diameter 60mmφ
, a compression ratio of 1.5), the rubber materials for the rubber substrate having the formulation shown in Table 1 and the rubber materials for the adhesive layer shown in Table 2 were used to form an adhesive layer (adhesive layer thickness: 0. Rubber base (width 35 mm x thickness 4 mm) whose top surface is covered with
) conditions for extruding; extrusion speed 5 m/min). Next, the top surface of the extrudate (rubber base) was coated with a PVC paste (after vacuum defoaming) having the foaming formulation shown in Table 3 to a thickness of 1 mm to form a final coating layer ( p
VC paste layer) was formed, and the extrudate was carried into a hot air tank, and vulcanization of the rubber substrate 1 and adhesive layer and heat gelation of the paste layer were simultaneously performed under conditions of 200° C.XIO minutes.

After leaving the Examples and Comparative Examples prepared in this manner for 2'4 hours at room temperature, the adhesion strength between the adhesive layer and the rubber substrate, and between the adhesive layer, the finish coating layer, and the adhesive layer was determined to be 180 Measured using a peel test (pulling speed: 10 cm/min).

From the test results shown in Table 4, the adhesion of the adhesive layer of each example to both the rubber substrate and the finish coating layer was good, and 5BRh)? It has been found that the use of IIM-combined three-component systems further improves the adhesion of the adhesive layer to the rubber substrate.

Table 4 also shows the rubber physical properties of the adhesive layer measured according to JIS K-6301. If SBR is excessive, it can be seen that the ozone resistance is not good.

In addition, all the finished coating films had a deep black color with rich texture. Furthermore, the expansion ratio of the PVC gelled layer was about 2 times.

(unit parts by weight) *Manufactured by Japan Synthetic Rubber Table 3 *Sumitomo Chemical (KK) manufacturing

[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. DESCRIPTION OF SYMBOLS 1... Rubber base, 3... Finishing coating layer, 5... Adhesive layer, D... Design surface. Patent applicant Figure 3

Claims (1)

[Claims] A rubber laminate in which a finish coating layer is formed of a gelled layer of PVC paste (hereinafter referred to as "PVC gelled layer") on a rubber base made of EPDM; A foamed rubber compound adhesive with a rubber component between the coating layer and a blended rubber having a composition of NBR: 40 to 80% by weight, EPDM: 20 to 60% by weight, and SBR: 0 to 35% by weight. A rubber laminate with a finish coating layer, characterized in that a layer is interposed therebetween.