JPH09227828A - Coating material for weather strip and production of weather strip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating material which has a freely controlled reaction time while it has assured durability of the curing agent of the coating material applied to the surface of a rubber material. SOLUTION: A glass run 1 is molded by extruding a rubber material from the main spinerette of an extruder, simultaneously coating the extrudate with a coating material 5 based on an isocyanato-reactive polyol and simultaneously performing the vulcanization of the rubber material and the baking of the coating material. The curing agent added to the principal component is a composition prepared by mixing 100 pts.wt. nonyellowing or difficultly yellowing isocyanate with 10-80 pts.wt. yellowing isocyanate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a urethane-based coating material applied to the surface of an extruded body of a rubber material which constitutes a weather strip of an automobile, and the above-mentioned coating material applied to the surface of the rubber material. The present invention relates to a method for manufacturing a weather strip.

[0002]

2. Description of the Related Art For example, in a weather strip typified by a glass run channel for an automobile, a portion having a sliding contact with a window glass is conventionally coated with a coating material having a high sliding property for the purpose of reducing a friction coefficient. It is being appreciated.

And as this coating method,
As shown in Japanese Patent Publication No. 7-88032, a heated rubber material is extruded from a main die of an extrusion molding machine, and at the same time as the extrusion molding, urethane is applied from an application die stacked on the outside of the main die. There is a method in which a coating material (coating liquid) made of a system resin or the like is supplied to the surface of the rubber material immediately after passing through the main die with an appropriate pressure, and the rubber is continuously coated in a predetermined width. According to this method, since the coating material is heated at the same time during the vulcanization step in which the extruded rubber material passes, the manufacturing work efficiency can be improved without a separate baking step.

On the other hand, the coating material is disclosed in, for example, Japanese Patent Application Laid-Open No. 7-150074, and the urethane coating material serving as the base layer is of a non-yellowing type which is a curing agent and an OH group polyol as a main component. There is a mixture of hexamethylene diisocyanate (HDI) prepolymer and the like. Further, the one disclosed in Japanese Patent Application Laid-Open No. 237448/1993 is a diphenylmethane diisocyanate (MD) of a yellowing type which is a curing agent in a polyol which is a main ingredient.
I) and the like are blended to improve the adhesion between the rubber material and the coating material.

[0005]

However, in the invention disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-150074, since the non-yellowing type HDI for paint is used as the curing agent, the above-mentioned problems are solved. The reaction immediately after extrusion molding becomes slow, and it takes about one month to reach the final physical properties. As a result, when the product is lacking in stability, and especially when the mixing ratio with the polyol is deviated, the physical properties become more unstable and the durability performance deteriorates, and sufficient quality assurance as a product cannot be achieved.

On the other hand, the invention disclosed in Japanese Patent Laid-Open No. 5-237448 discloses a yellowing type MDI in which the curing agent is for casting.
Therefore, the reaction after extrusion molding becomes faster, and the curing agent cures in the material passage communicating with the coating die during the above-mentioned extrusion molding, resulting in insufficient coating on the rubber material surface. Will end up. As a result, a uniform coating film cannot be obtained, and the coating width on the surface of the rubber material is narrowed, or the coating surface is partially lost to expose the rubber surface in a streak pattern.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances.
A coating material for a weather strip, which is applied to the surface of the rubber material at the same time when the rubber material is extruded from a die of an extruder and then baked on the rubber material during vulcanization of the rubber material, which is an isocyanate group. It is characterized in that a curing agent prepared by mixing a non-yellowing / slightly yellowing isocyanate and a yellowing isocyanate is mixed with a main component containing a polyol that reacts with.

The invention according to claim 2 is characterized in that the curing agent is prepared by mixing 10 to 80 parts by weight of yellowing isocyanate with 100 parts by weight of non-yellowing / yellowing resistant isocyanate. There is.

The third aspect of the present invention is characterized in that the curing agent contains 25 to 65 parts by weight of yellowing isocyanate with respect to 100 parts by weight of non-yellowing or hardly yellowing isocyanate.

According to a fourth aspect of the present invention, a rubber material is extruded from a main die of an extrusion molding machine, and at the same time as this extrusion molding, a main component of a polyol that reacts with an isocyanate group is not yellowed on the surface of the rubber material. A coating material composed by mixing a curing agent composed of a yellowing-resistant isocyanate and a yellowing-resistant isocyanate is applied from a coating die attached to the main die, and then vulcanization of the rubber material is performed. At the same time, the coating material is baked on the surface of the rubber material.

The present invention is a manufacturing method in which the coating material is applied to the surface of the rubber material simultaneously with extrusion molding of the rubber material, and the coating material is baked by utilizing high heat (about 200 ° C.) during the vulcanization treatment of the rubber material. On the premise that the curing agent of the coating material is a composition in which yellowing isocyanate is added to non-yellowing / hard yellowing isocyanate and the mixing ratio is changed, the curing reaction time after extrusion can be set arbitrarily. I was able to do it.

Specifically, as in the invention of claim 2, when the yellowing isocyanate is mixed in a ratio of 10 to 80 parts by weight with respect to 100 parts by weight of the non-yellowing / hardly yellowing isocyanate, after extrusion molding. The reaction was completed in about 3 to 14 days, the physical properties were stabilized, and sufficient durability performance was secured. Moreover, the rapid reaction is suppressed by the mixing ratio of the both, and the coating material in the material passage near the coating die during the continuous extrusion operation time of the extruder for one day, for example, 7 to 8 hours. The liquidity of was secured.

The mixing ratio of the two is preferably 25 to 65 parts by weight of yellowing isocyanate with respect to 100 parts by weight of the non-yellowing or hardly yellowing isocyanate described in claim 3.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION In this embodiment, as shown in FIG. 1, the present invention is applied to an extruded product of a glass run 1 which is a weather strip having a substantially U-shaped cross section and made of rubber as a material. The coating material 5 is applied to the surface of the central portion of 2 and the inner surfaces of the seal lips 3 and 4.

FIG. 2 shows a die structure of an extrusion molding machine for producing the glass run 1. The main die 6 provided at the tip of the cylinder barrel is made of a rubber material 1a having a shape corresponding to the cross-sectional shape of the glass run 1. The material passage 7 is formed so as to penetrate therethrough, and three screw holes are provided at a relatively upper portion thereof, and two positioning holes are provided at a relatively lower portion thereof. A coating mouthpiece 9 is attached to the front end of the main mouthpiece 6 via a bolt 8 screwed into a screw hole of the main mouthpiece 6. The coating die 9 is formed with an opening 10 that is slightly larger than the material passage 7 of the main die 6, and
Three coating liquid supply pipes 11 are fixed on the front side. In addition, a groove-shaped liquid supply passage 13 extending from a passage hole 12 connected to the coating liquid supply pipe 11 to a desired liquid application site is formed in a fan-like shape on the back surface of the coating die 9. The liquid discharge port 14 at the tip of the liquid supply passage 13 is formed on the inner wall surface of the opening 10.

Further, the liquid supply pipe 11 is connected to a coating liquid supply device via a rubber tube or the like (not shown) so that the coating liquid, which is a coating material made of urethane resin or the like, is supplied at an appropriate pressure. It has become. In addition, the coating liquid supply device is provided with a static mixer that mixes the main component and two types of curing agents described below.

On the outlet side of this extruder, a vulcanizing apparatus (not shown) for vulcanizing the rubber material extruded into a predetermined cross-sectional shape by heating at a temperature of about 150 to 250 ° C. by high frequency heating or the like. Are arranged.

The coating liquid is prepared by mixing a main component such as a polyol having two or more active hydrogens that react with isocyanate groups with a non-yellowing / non-yellowing isocyanate and a yellowing isocyanate in a predetermined ratio. A compound obtained by adding a curing agent.

That is, the polyol as the main component is generally a polyether polyol obtained by polymerizing propylene oxide or ethylene oxide, a polyester obtained by condensation polymerization of an organic acid such as adipic acid and a hydroxy component such as a short chain diol. There are polyols and the like. Furthermore, there are polytetramethylene ether glycol, lactone-based polyol, acrylic-based polyol, polycarbonate-based polyol, castor oil-based polyol, polybutadiene-polyol, bisphenol-based polyol, and the like.

On the other hand, as the non-yellowing / hard yellowing isocyanate of the curing agent, HDI (hexamethylene diisocyanate), XDI (xylene diisocyanate), hydrogenated TD
I (tolylene diisocyanate), hydrogenated MDI (diphenylmethane diisocyanate), hydrogenated XDI, IPDI
(Isophorone diisocyanate), LDI (lysine diisocyanate), IPCI (isopropridene bisisocyanate) or more alone or burette modified,
Derivatives such as isocyanurate modified, TMP modified (trimethylolpropane), uretdione modified, and prepolymer modified with various polyols are considered, and as yellowing isocyanate, MDI (diphenylmethane diisocyanate), crude MDI, TDI (tolylene dirange) is considered. Isocyanate), TODI (dimethyl biphenyl diisocyanate), NDI (naphthalene diisocyanate) or a simple substance or a derivative of various polyols such as prepolymer modification, carbodiimide modification, isocyanurate modification, or the like can be used.

[0021]

EXAMPLES Hereinafter, the durability performance of the coating material and the extrudability of the material will be described in detail based on each example.

As shown in Table 1, the coating material was an ether / ester group-containing polyol (Desmophen 1150 (Sumitomo Bayer Urethane)) as the main component, and a non-yellowing / hard yellowing type HDI prepolymer (Sumi Joule N3500 (Sumitomo Bayer Urethane) (hereinafter,
It is called HDI. ) And yellowing type MDI prepolymer (Sumijour E21-1 (Sumitomo Bayer Urethane))
(Hereinafter, referred to as MDI) was prepared.

The polyol as the main ingredient is 100 parts by weight, and the mixing ratio of the curing agent is HDI 10 in each example.
10 parts by weight of MDI (Example 1), 25 parts by weight (Example 2), 50 parts by weight (Example 3), 65 parts by weight (Example 4), and 100 parts by weight of 0 parts by weight, respectively. About 60 parts by weight of a curing agent was added so that the ratio was that of Example 5).

In Comparative Examples 1 to 3, HDI was 100 parts by weight and MDI was 0 parts by weight.
MDI was set to 100 parts by weight with respect to 0 part by weight of I. Furthermore, in Comparative Example 5, HDI was MD with respect to 100 parts by weight.
I was also 100 parts by weight, and in Comparative Example 6, HDI was 100 parts by weight and MDI was 300 parts by weight.

[0025]

[Table 1]

As described above, the test piece 20 was tested for durability performance and material extrudability based on the mixing ratio of HDI and MDI. The durability performance is obtained by applying a coating film of the coating material 22 with a mixing ratio as described above to a uniform thickness in the central longitudinal direction of the upper surface of the rubber plate 21 (rubber material) extruded as shown in FIG. The tip portion 23a of the substantially U-shaped glass plate 23 was vertically contacted with the upper portion and slid in the longitudinal direction while applying a pressing force of about 3 kg / m from above. Dust and water were applied to the surface of the coating material 22 about once / 500 times, and peeling of the coating material 22 was observed. From the day of extrusion molding 1,
The test was conducted after 3, 7, 14, and 30 days, and the number of days until the number of peeling occurrences reached 10,000 was taken as the number of days required to satisfy the durability performance.

As for the extrudability of the material, as shown in FIG. 4, the continuous extrusion time from the die was the test piece 3.
The extrusion was performed for 8 hours, and the time for which the coating range of the coating material 32 on the surface of the rubber plate 31 was abnormal and the rubber surface was partially exposed was checked. Also, the main agent and curing agent are 6
The temperature was kept at 0 ° C., both were rapidly stirred so that air was not mixed, and the viscosity after 1 to 4 hours was measured with a B-type viscometer (the temperature was kept at 60 ° C. even after mixing).

(1) Comparative Example 1 when MDI was not added
As shown in, the initial durability is low and it takes about one month to satisfy the performance. In addition, Comparative Example 2 using a catalyst (dibutyltin, dilaurate) in order to enhance the reaction
As shown in 3, the period until the endurance performance is satisfied is 20
Although it was shortened to 10 days, it was difficult to disperse evenly in a highly viscous material with a very small amount of addition when the catalyst was used in this way, and the durability after 1 week after extrusion molding was increased. The number of times was 2,000 to 10,000, and the durability performance varied.

(2) When MDI is set to 10 parts by weight and 25 parts by weight with respect to 100 parts by weight of HDI, as shown in Examples 1 and 2, up to a level satisfying the durability performance in about 2 to 1 week. The reaction was faster. In particular, it was found that, with 25 parts by weight, 80% of the reaction was completed in one week, and the durability was 8,000 times, reaching a level where there was no problem in practical use.

(3) Further, as shown in Examples 3 to 5, M
When DI is increased to 50, 65, 80 parts by weight with respect to 100 parts by weight of HDI, the reaction period until satisfying the durability performance is further shortened to 5 to 3 days, and the durability count after one week is 10,000. It turned out that excellent durability performance was obtained. Therefore, if MDI is set to 25 to 80 parts by weight with respect to 100 parts by weight of HDI, sufficient durability can be ensured, and the required number of days until the durability is satisfied is 8 to 3 days. Since the reaction is completed from the manufacture of the product to the shipment, it becomes possible to guarantee the quality.

(4) Next, observing a coating failure due to clogging of the coating material in the material passage during extrusion molding,
When a catalyst is used as the curing agent (Comparative Examples 2 and 3), the apparent reaction (gelation) is accelerated, the composition is cured in about 3.5 to 2 hours, and coating failure is likely to occur.

(5) However, in the case where the ratio of MDI is 10 to 80 parts by weight with respect to 100 parts by weight of HDI (Examples 1 to 1).
In the case of 5), it took about 4 hours or more until the fluidity of the coating material disappeared, and the coating failure actually occurred after 8 to 7.5 hours. This time zone generally corresponds to the daily operating time of the extruder. Therefore, the continuous extrusion molding for 7 to 8 hours is possible, and a sufficient time that does not hinder the operation can be secured.

Therefore, when comprehensively judging the durability performance and the extrudability of the material, the mixing ratio of the hardening material is 100% of HDI.
It has been revealed that it is desirable to set MDI to 10 to 80 parts by weight with respect to parts by weight, and further more excellent effects can be obtained by setting MDI to 25 to 65 parts by weight.

The vulcanization temperature in the vulcanizer after being extruded from the extruder is set to 150 to 250 ° C.

When performing extrusion molding using the above-mentioned extrusion molding machine, the liquid is discharged from the liquid discharge port 14 to a predetermined portion of the molded product extruded into a predetermined shape through the material passage 7 of the main die 6. Since the coating solution is continuously applied, extrusion molding and application of the coating solution can be simultaneously processed.

Furthermore, since the extrusion molding of the rubber material and the coating of the coating liquid can be carried out at the same time, 150 to 250 are simultaneously applied in the vulcanization step of the coating material being the rubber material.
Since it receives a heat of ° C and becomes a kind of baking state, a firm coating film is formed without a separate baking step.

In order to ensure the slidability of the coating liquid, a silicone compound such as silicone oil is usually used in the coating liquid.
Fluorine compounds such as tetrafluoroethylene and resin powder are added.

[0038]

As is clear from the above description, according to the present invention, it is possible to reduce the manufacturing man-hours by simultaneously treating the rubber material and the coating material, and in particular, the non-yellowing / difficulty as the curing agent. Since a mixture of yellowing isocyanate and yellowing isocyanate was used, by changing the mixing ratio, the curing reaction time after extrusion molding can be arbitrarily set and continuous for a long time by an extruder. Enables molding work.

Therefore, it becomes possible to obtain the final physical properties from the manufacturing to the shipping of the weather strip, in particular, sufficient durability performance, to ensure the quality by stabilizing the product and to improve the productivity by continuous operation. .

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a glass run used in an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view showing a die structure of an extrusion molding machine used in this example.

FIG. 3 is a perspective view showing a test material used for a durability performance test.

FIG. 4 is a perspective view showing a test material used for a continuous extrusion molding time test.

[Explanation of symbols]

 1 ... Glass run (weather strip) 1a ... Rubber material 5 ... Coating material 6 ... Main mouthpiece 9 ... Coating mouthpiece

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location B60R 13/06 B60R 13/06 C09D 5/00 PPK C09D 5/00 PPK // B29K 21:00 B29L 31:30

Claims (4)

[Claims] 1. A coating material for a weather strip, which is applied to the surface of the rubber material at the same time when the rubber material is extruded from a die of an extruder and then baked on the rubber material during vulcanization of the rubber material. A coating material for a weather strip, characterized in that a main agent mainly composed of a polyol that reacts with an isocyanate group is mixed with a curing agent obtained by mixing a non-yellowing / hard yellowing isocyanate and a yellowing isocyanate. 2. The curing agent comprises 10 parts by weight of yellowing isocyanate with respect to 100 parts by weight of non-yellowing or hardly yellowing isocyanate.
The coating material for the weather strip according to claim 1, wherein the coating material is mixed in an amount of -80 parts by weight. 3. The curing agent comprises 25 parts of yellowing isocyanate based on 100 parts by weight of non-yellowing / hard yellowing isocyanate.
The weather strip coating material according to claim 1, wherein the coating material is mixed in an amount of about 65 parts by weight. 4. A rubber material is extruded from a main die of an extruder, and at the same time as this extrusion, a non-yellowing / non-yellowing isocyanate is formed on the surface of the rubber material as a main component of a polyol that reacts with an isocyanate group. And a coating material composed by mixing a curing agent consisting of yellowing isocyanate, is coated from the coating die attached to the main die, and then, simultaneously with the vulcanization of the rubber material, the coating material is A method for producing a weatherstrip in which a surface of a rubber material is baked.