JPH07169307A - Sealant for vehicle lamp - Google Patents

Abstract

PURPOSE:To provide a sealant for a vehicle lamp, excellent in tightness and adhesiveness and capable of exhibiting easy interface separation by forcible separation by blending hydrogen adding stylene-butadiene copolymers, petroleum resins, and a hydrocarbon plasticizer. CONSTITUTION:An adhesive sealant for bonding a lens of a lamp for a vehicle to a housing is composed of an A component, a B component, and a C component as follows: the A component includes one or more kinds of copolymers of a hydrogen adding sthylene-butadiene copolymer, water adding stylene- isoprene copolymer, and denatured copolymers thereof; the B component is an adhesiveness applying agent of one or more kinds of a petroleum resin, a terpene resin, a rosin resin, a coumarone-indene resin, hydrogen additives thereof and denatured resins thereof; and the C component includes a hydrocarbon plasticizer. 10-50 parts by weight of the B component and 50-250 parts by weight of the C component are mixed with 100 parts by weight of the A component, where the content of the A component is 16-60wt% with respect to the whole of the sealant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sealing material for a vehicle lamp for adhesively sealing a lens of a vehicle tail lamp or a headlamp and a housing. Specifically, it has excellent adhesion and adhesion to polyolefin resin, ABS resin, acrylic resin, polycarbonate resin, glass, etc., which will be lenses and housings, and easily exhibits interfacial peeling by forced peeling. The present invention relates to a sealing material for a vehicle lamp.

[0002]

2. Description of the Related Art Conventionally, a vehicular lamp is basically composed of a light source, a bowl-shaped housing (reflector), and a lens, and a sealing material is used to seal the open surface of the housing with the lens. And the light source is fixed to a predetermined position (usually the bottom) of the housing to form a lamp. A hot-melt composition having high adhesiveness is generally used as a sealant between the housing and the lens.

Hot melt compositions used as sealing materials for vehicle lamps include ethylene / vinyl acetate copolymer (EVA) and styrene / isoprene copolymer (SI).
S), styrene / butadiene copolymer (SEBS), butyl rubber (IIR), ethylene / propylene copolymer rubber (EPR) and modified products of these as base polymers,
A petroleum resin, a terpene resin, a rosin resin, a chroman indene resin, and a composition obtained by adding a hydrogenated product or a modified product thereof to the base polymer as a tackifier are used. Such a sealing material is prepared by blending 100 to 200 parts by weight of a tackifier with 100 parts by weight of a base polymer.

These sealing materials (hot melt composition)
The manufacturing of the vehicle lamp using the, the sealing material in the concave groove formed in the housing of the vehicle lamp is heated and melted by using a hot melt applicator or the like, and then the convex portion formed around the lens is formed. This is done by loosely fitting the parts. In addition, the adhesion of the housing and the lens that are adhered,
Usually, it is held more securely by various fastening members. The above-mentioned various sealing materials have very excellent adhesiveness, and reliably adhere the housing and the lens together, and also provide good watertightness between them, that is, inside the lamp.

By the way, from the viewpoint of environmental protection and the like, it has recently been required that automobile parts can be easily recycled, and vehicle lamps are no exception. However, in a conventional vehicle lamp using such a sealing material, it is difficult to disassemble the housing and the lens at the time of disassembling, and even when both can be disassembled, the sealing material is removed from the housing and the lens. Cannot be easily peeled off.
Therefore, although the conventional vehicle lamp is excellent as a structure, it is extremely disadvantageous in terms of recycling, and the advent of a sealing material for a vehicle lamp that can improve this point is desired.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art, and to bond the housing of the vehicle lamp and the lens with sufficient adhesive strength and liquid tightness. It is another object of the present invention to provide a sealing material for a vehicle lamp that can be easily peeled off at the interface at the time of disassembling and allows easy recycling of the housing and the lens.

[0007]

In order to achieve the above object, a first aspect of the present invention is an adhesive sealing material for a lens of a vehicle lamp and a housing, which comprises the following components A and B:
Component and C component A component Hydrogenated styrene / butadiene copolymer, hydrogenated styrene / isoprene copolymer, and one or more copolymers selected from the group consisting of modified products thereof;
Component B One or more tackifiers selected from the group consisting of petroleum resins, terpene resins, rosin resins, coumarone indene resins, hydrogenated products and modified products thereof; C
Component 10 to 50 parts by weight of the component B and 50 to 250 parts by weight of the component C per 100 parts by weight of the component A, containing at least one plasticizer selected from hydrocarbon-based plasticizers.
Provided is a sealing material for a vehicle lamp, characterized in that the content of the component A is 15 to 60% by weight in the total amount of the sealing material.

A second aspect of the present invention is an adhesive sealing material for a lens of a vehicle lamp and a housing, which comprises the following A component, B component, C component and D component A component hydrogenated styrene-butadiene. One or more copolymers selected from the group consisting of copolymers, hydrogenated styrene / isoprene copolymers, and modified products thereof;
B component Petroleum resin, terpene resin, rosin resin, chroman indene resin, one or more tackifiers selected from the group consisting of hydrogenated products and modified products thereof; C
Component One or more plasticizers selected from hydrocarbon-based plasticizers; Component D, one of thermoplastic polymers other than the component A
And a total of 100 of the above-mentioned A component and D component.
10 to 50 parts by weight of the B component, 50 to 250 parts by weight of the C component, and 15 to 60% by weight of the A component in the total amount of the sealing material, relative to parts by weight. The present invention provides a sealant for a vehicle lamp.

The sealing material for a vehicle lamp according to the present invention will be described in detail below. A sealing material for a vehicle lamp according to the first aspect of the present invention (hereinafter referred to as a sealing material) is an A component which is a base polymer; a B component which is a tackifier;
The component C is a plasticizer; and the sealing material of the second embodiment further contains a component D which is a base polymer together with the component A.

In the sealing material of the present invention as described above, the component A serving as the base polymer is a hydrogenated (hereinafter referred to as hydrogenated) styrene / butadiene copolymer, a hydrogenated styrene / isoprene copolymer, and modifications thereof. It is one or more copolymers selected from the group consisting of the following:

The hydrogenated styrene / butadiene copolymer is
A hydrogenated product of a random copolymer of styrene and butadiene and a hydrogenated product of a block copolymer of styrene and butadiene, especially a water of a so-called SBS block copolymer in which styrene blocks are bonded to both ends of a butadiene block. An accessory (abbreviated as SEBS) is preferably exemplified. In the hydrogenated styrene / butadiene copolymer used in the present invention, the ratio of styrene to butadiene and the hydrogenation ratio are not particularly limited.

On the other hand, the hydrogenated styrene / isoprene copolymer is a hydrogenated product of a random copolymer of styrene and isoprene, or a hydrogenated product of a block copolymer of styrene and isoprene. A hydrogenated product of a so-called SIS block copolymer (abbreviated as SEPS) bonded to both ends of an isoprene block is preferably exemplified. In the hydrogenated styrene / isoprene copolymer used in the present invention, the ratio of styrene to isoprene and the hydrogenation ratio are not particularly limited.

Further, the hydrogenated styrene-butadiene copolymer and hydrogenated styrene
As the modified product of the isoprene copolymer, various compounds can be used, and one example is a product obtained by introducing a polar group such as a carboxyl group or a hydroxyl group into a part of these copolymers.

In the sealing material of the present invention, the tackifier B component is selected from the group consisting of petroleum resin, terpene resin, rosin resin, coumarone indene resin, and hydrogenated and modified products thereof. There are one or more of these, and various known ones can be used. Above all,
Hydrogenated petroleum resins and modified terpene resins are preferably used.

In the sealing material of the present invention, the C component is at least one plasticizer selected from hydrocarbon plasticizers. As the hydrocarbon-based plasticizer, various known and commercially available products can be used. Specifically, liquid paraffin,
Preferable examples are polybutene and liquid polybutadiene. As a compounding agent added to various rubbers and resin compositions, phthalic acid ester, aliphatic dibasic acid ester,
Glycol esters, phosphate esters, epoxy plasticizers and the like are generally commercially available, but in the present invention,
These are not used, but a hydrocarbon plasticizer is used.

In the sealing material of the second aspect of the present invention, in addition to these components A, B and C, a component D which forms a base polymer together with the component A is further contained. In the second aspect of the present invention, the inclusion of such a component D has advantages such as excellent adhesion to an adherend and excellent sealing force during heating.

The component D used in the present invention is at least one selected from thermoplastic polymers other than the component A. Such thermoplastic polymers include ethylene
Vinyl acetate copolymer (EVA), ethylene / ethyl acrylate copolymer (EEA), styrene / isoprene block copolymer (SIS), styrene / butadiene block copolymer (SBS), butyl rubber (IIR), ethylene / propylene Copolymer rubber (EPR) and the like are preferably exemplified. In particular, styrene / isoprene block copolymer, ethylene / propylene copolymer rubber, butyl rubber and the like are preferably used.

In the sealing material of the present invention (both the first and second embodiments) containing each of these components as essential components, the content of the component A is 15 to 60% by weight based on the total amount of the sealing material. If the content of the component A is less than 15% of the total amount of the sealing material, defects occur in the decomposability between the lens and the housing when the lamp is disassembled, deterioration of the sealing material peeling property, deterioration of weather resistance, and the like. If more than 60% by weight is blended, insufficient adhesion cannot be obtained, and the melt workability may be deteriorated due to an increase in melt viscosity.

The content of the component A is preferably about 20 to 40% by weight of the total amount of the sealing material. By setting the blending amount of the component A in the above range, favorable results are obtained in terms of various properties required as a hot melt for a lamp, such as a balance of adhesiveness and sealing properties, melt viscosity, and heat resistant flowability.

Further, the blending amount of the component B which is a tackifier is 100 parts by weight of the base polymer, that is, 100 parts by weight of the component A in the first embodiment, and a total of 100 parts of the components A and D in the second embodiment. It is 10 to 50 parts by weight with respect to parts by weight. In the sealing material of the present invention, by setting the blending amount of this component B in the above range, excellent sealing properties (adhesiveness) and releasability are achieved in a good balance. If the amount of the component B is less than 10 parts by weight with respect to 100 parts by weight of the base polymer, a disadvantage occurs in that sufficient adhesive force cannot be obtained, and if it is more than 50 parts by weight, the lamp is Inconvenience is caused in terms of degradability of the lens and the housing at the time of disassembling and deterioration of peeling property of the seal material.

The amount of component C, which is a plasticizer, is 50 to 250 parts by weight with respect to 100 parts by weight of the base polymer. If the blending amount of the C component is less than 50 parts by weight with respect to 100 parts by weight of the base polymer, sufficient adhesive force cannot be obtained,
Inconvenience is caused in terms of deterioration of discharge workability due to an increase in melt viscosity, and conversely, when it is blended in an amount of more than 250 parts by weight, decomposability between the lens and the housing at the time of disassembling the lamp and deterioration of peeling property of the sealing material, There is a problem in that the heat resistant flow temperature is lowered.

In the second aspect of the present invention, in addition to the component A as a base polymer, a thermoplastic polymer D is used.
The ingredients are blended. The blending amount of the D component is not particularly limited, and may be blended so that the content of the A component in the total amount of the sealing material is 15 to 60% by weight in consideration of the balance with other components.

Preferably, the blending amount of the D component is the A component /
The amount ratio of the D component is about 90/10 to 50/50. D
By adjusting the blending amount of the components within the above range, the balance between the desired sealability and peelability, melt viscosity, heat / cold resistance, weather resistance, etc. A favorable result is obtained.

The sealing material of the present invention basically has the above composition, but in addition to this, generally commercially available waxes and inorganic fillers are added within the range not departing from the gist of the present invention. Good.

As the waxes, paraffin wax, microcrystalline wax, Fischer-Tropsch wax, low molecular weight polyethylene, low molecular weight polypropylene, actactic polypropylene, and modified products thereof are preferably used.

As the inorganic filler, calcium carbonate, barium sulfate, talc, clay, titanium oxide, carbon black, white carbon and the like are preferably used.

The seal material of the present invention is used in the range of 150 to 2 when used.
It is melted at 00 ° C. Therefore, a heat stabilizer may be required. Furthermore, depending on the application, it may be necessary to add a weather resistance stabilizer. Therefore, it is preferable to use a stabilizer that has the properties of both a heat stabilizer and a weathering stabilizer.

Examples of such stabilizers include hindered phenol anti-aging agents and hindered amine anti-aging agents. Further, the blending amount may be appropriately determined according to the stabilizer.

In order to adjust the sealing material of the present invention as described above, the components A to C, the component D, and further the optional components to be blended as necessary are melted in accordance with the components by using an apparatus such as a kneader. It is carried out by melt mixing at a temperature, usually about 180 to 200 ° C.

There is no particular limitation on the method for adhering the lens of the vehicle lamp and the reflector using the sealing material of the present invention, and various methods similar to those for ordinary hot melt compositions can be used. For example, it is carried out by a method using a hot melt applicator as described above.

A commercially available hot melt applicator comprises a hot melt melting section, a pump pressure feeding section, a hose and a gun. The melting part is generally of a tank type, a pail type or a drum type. Further, a piston type, a gear pump type, an extrusion type and the like are known as the pressure feeding section. Further, a hose having a structure and characteristics capable of holding a constant temperature is used, and the gun is an automatic gun or a hand gun. The sealant of the present invention is well suited for such commercially available hot melt applicators.

A vehicle lamp manufactured by using the sealing material of the present invention is made of polyolefin resin, AB.
Regardless of whether the lens or housing is made of any material such as S-based resin, acrylic resin, polycarbonate resin, or glass, the lens and housing are adhered to each other with good adhesive force and liquid-tightness. The lens and the housing can be easily separated by the forced separation, and the sealing material can be easily removed from the lens and the housing so that the lens and the housing can be recycled.

[0033]

EXAMPLES The present invention will be described in more detail with reference to specific examples of the present invention. [Examples] Various sealing materials were prepared by heating and melting with a kneader and mixing at the weight ratio (parts by weight) of each component shown in Table 1 (Nos. 1 to 3) below.

[0034]

[Table 1]

[0035]

[Table 2]

[0036]

[Table 3]

In the above Table 1, Component A: Kraton G-1652; Hydrogenated styrene / butadiene block copolymer (manufactured by Shell Chemical Co.) Septon 2002; Hydrogenated styrene / isoprene block copolymer (manufactured by Kuraray Co.) Component B Escoletz 5320; Hydrogenated petroleum resin (manufactured by Tonex Co.) C component HV-100; Polybutene (manufactured by Nippon Oil Co., Ltd.) HV-300; Polybutene (manufactured by Nippon Oil Co., Ltd.) D component Quintac 3421; Styrene-isoprene block copolymer (Japan Seon Co., Ltd.) EPT-0045; ethylene / propylene copolymer rubber (Mitsui Petrochemical Co., Ltd.) PB-402; butyl rubber (Polcer Co., Ltd.) Other components Neowax L; polyethylene wax (Yasuhara Chemical Co., Ltd.) Sun Attack R; Atactic polypropylene (thousands) Leaf Fine Chemicals Co., Ltd.) Carplex 1120; White Carbon (Shionogi Pharmaceutical Co., Ltd.) Irganox 1020; Anti-aging agent (Bindered Phenolic Antioxidant, manufactured by Nippon Ciba Geigy)

Using the various sealing materials thus prepared, the following various tests were conducted.

[Viscosity] The viscosity was measured at 190 ° C. using a B type viscometer.

[Hardness] After cooling and solidification, JIS K630
According to 1 (Shore A), the value after 5 seconds at 20 ° C. was measured.

[Heat-resistant flow temperature] A sample (sealing material) 10 adjusted to a size of 10 × 10 × 5 mm was brought into close contact with an aluminum plate 11 as shown in FIG. 1 and then in an electric oven adjusted to a predetermined temperature. The shape-retaining property of the sample after left standing vertically for 24 hours was confirmed. The upper limit of the temperature at which the sample 10 can retain its shape is the heat resistant flow temperature.

[Sealing Property] As shown in FIGS. 2 (a) and 2 (b), a sealing material is used by using a lamp model comprising a housing 14 made of polypropylene resin (PP) and a lens 12 made of acrylic resin (PMMA). After melting and discharging 10 into the groove 16 of the housing, the peripheral portion of the lens 12 is
It was inserted in 6 and the lamp model was assembled. After the sealant 10 is sufficiently cooled and solidified, 0.1 kgf / cm ² of air (air) is injected from the injection port 18 formed on the bottom surface of the housing 14 to maintain the airtightness of the lamp model for 10 minutes or more. Was marked with ○ and the others were marked with ×. In this test,
An example in which mechanical fastening is performed using the fastening member 20 shown in (b) is method A, and an example in which mechanical fastening is not performed is method B. In the above test, the housing 1
The thickness a of lens 4 and the thickness b of lens 12 are 2 mm, and the groove 16
Has a width c of 4 mm and a depth d of 7 mm. Further, in method A, there is 1 between the fastening member 20 and the upper surface of the lens 12.
with a gap e of mm.

[Adhesiveness] After melt-discharging the sealing material 10 onto the JIS No. 6 cotton canvas 22, various adherends (various resins and glass) 24 are pressure-bonded to prepare a test piece as shown in FIG. 200 minutes per minute after the sealant has sufficiently cooled and solidified
A 180 ° peeling test was performed at a speed of mm, and the peeled state was observed. In addition, apply the sealing material to cotton canvas in the form of beads,
After pressure-bonding the adherend, a test piece having a size of 100 to 120 × 25 (mm) and a thickness of 2 mm was prepared. The sealing material 10 itself was designated as CF when it was cohesively broken, and AF when it was interfacially separated between the adherend and the adhesive interface. Further, AF / CF was used when cohesive failure and interfacial peeling were mixed, and TCF was used when cohesive failure occurred when a thin layer was formed near the interface of the adherend.

The above test results are shown in Table 2 below (parts 1 to 1).
It is shown collectively in 3).

[0045]

[Table 4]

[0046]

[Table 5]

[0047]

[Table 6]

In Table 2 above, PP; Nobrene MH-8 (polypropylene resin
Mitsubishi Petrochemical Co., Ltd. ABS; Ube Sikon GSE (acrylonitrile
Butadiene / styrene resin made by Ube Saikon) PMMA; Acrylite 001 (acrylic resin made by Mitsubishi Rayon) PC; LS2-111 (polycarbonate resin made by Nippon GE Plastics) glass; soft glass

As shown in Table 2 above, a hydrogenated styrene / butadiene block copolymer is selected as the component A,
In Invention Examples 1 to 5 and Comparative Examples 1 to 4 in which 55 parts by weight of polyethylene wax was added in addition to the essential components, Invention Examples 1 to 5 had good sealability and adhesion to various lenses and housing materials. In contrast to the interfacial peeling (AF) exhibited in the property test, Comparative Example 1 containing no hydrogenated petroleum resin as the B component and Comparative Example 3 in which the content of the polybutene as the C component is below the lower limit satisfy the sealing property. In addition, in Comparative Examples 2 and 4 in which the amounts of the B component and the C component exceeded the upper limits, a fracture state other than interfacial peeling is exhibited depending on the adherend.

Inventive Examples 6 and 7 and Comparative Example 5 in which a hydrogenated styrene / isoprene block copolymer was selected as the component A, and an inventive example containing a styrene / isoprene block copolymer (component D) as the base polymer. 8,
In Comparative Example 9 and Comparative Example 6, Invention Examples 6 to 9 have good sealability although they require mechanical fastening, and further exhibit interfacial peeling (AF) in the adhesion test, while In Comparative Example 5 in which the amount exceeded the upper limit, the sealing property could not be satisfied, and in Comparative Example 6 in which the amount of D component was large and the amount of A component was less than the lower limit, some adherends exhibited fracture states other than interfacial peeling. .

Further, as shown in Inventive Examples 10 and 11 and Comparative Example 7, even in the system in which the upper limit amount of the component C was blended, Inventive Examples 10 and 11 had good sealability, and further in the adhesion test. In contrast to the interfacial peeling, in Comparative Example 7 in which the amount of the component A in the base polymer is small, some adherends exhibit a broken state other than the interfacial peeling.

Further, in Comparative Example 8, a styrene / isoprene block copolymer and an ethylene / propylene copolymer rubber were used as base polymers, and in Comparative Example 9, a hydrogenated styrene / butadiene block copolymer and butyl rubber were used as a base polymer. Although the conventional sealing materials for vehicle lamps are shown below, all exhibit excellent sealing properties, but exhibit cohesive failure (CF) for various adherends. From the above results, the effect of the present invention is clear.

[0053]

As described in detail above, the sealing material for a vehicle lamp according to the present invention can bond the housing of the vehicle lamp and the lens with sufficient adhesive strength and liquid tightness (sealability). In addition, the interface can be easily peeled off at the time of dismantling, the housing and the lens can be easily disassembled, and the sealing material can be more easily peeled from the housing and the lens for recycling, which is environmentally friendly and economical. It shows a great effect in terms of sex.

[Brief description of drawings]

FIG. 1 is a conceptual diagram for explaining a method of heat resistant flow temperature test of a sealing material of a vehicle lamp.

FIG. 2 is a conceptual diagram of a housing, a lens, and a fastening member for performing a sealability test of a sealing material of a vehicle lamp.

FIG. 3 is a conceptual diagram for explaining a method of an adhesion test of a sealing material of a vehicle lamp.

[Explanation of symbols]

 10 Sealing Material 11 Aluminum Plate 12 Lens 14 Housing 16 Groove 18 Injection Port 20 Fastening Member 22 Canvas 24 Adherend

Claims (2)

[Claims] 1. An adhesive sealant for a lens of a vehicle lamp and a housing, which comprises the following components A, B and C: component A hydrogenated styrene / butadiene copolymer, hydrogenated styrene / isoprene copolymer. , And one or more copolymers selected from the group consisting of modified products thereof; Component B, selected from the group consisting of petroleum resins, terpene resins, rosin resins, coumarone-indene resins, hydrogenated products and modified products thereof. 10 to 50 parts by weight of the component B based on 100 parts by weight of the component A. A sealing material for a vehicle lamp, comprising 50 parts by weight and 50 to 250 parts by weight of the C component, and the content of the A component in the total amount of the sealing material is 15 to 60% by weight. 2. An adhesive sealing material between a lens of a vehicle lamp and a housing, which comprises the following components A, B, C and D: component A hydrogenated styrene / butadiene copolymer, hydrogenated styrene / isoprene. Copolymer, and one or more copolymers selected from the group consisting of these modified products; B component Petroleum resin, terpene resin, rosin resin, chroman indene resin, hydrogenated products and modified products thereof One or more tackifiers selected from the group; C component, one or more plasticizers selected from hydrocarbon-based plasticizers, and D component, one or more thermoplastic polymers other than the A component. 10 to 50 parts by weight of the B component and 50 parts by weight of the C component with respect to a total of 100 parts by weight of the A component and the D component.
~ 250 parts by weight, the above A in the total amount of sealing material
A sealing material for a vehicle lamp, wherein the content of the component is 15 to 60% by weight.