JP2003042297A - Packing - Google Patents

Abstract

(57) [Summary] An object of the present invention is to provide a gasket having a suitable cushioning property and adhesiveness, having excellent airtightness and waterproofness, and having a stable shape and good handling. SOLUTION: The hardness is 15 to 60, 5 with a JIS A hardness tester.
A packing obtained by laminating a rigid base material (rigid layer) 3 on one side of an elastic sheet (elastic layer) 2 having a density exceeding 00 kg / m ³ and punching it into a predetermined shape. One.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packing suitable for improving the airtightness and waterproof performance by hermetically sealing the case of various electronic parts such as mobile phones, digital cameras and car navigations, and the periphery of liquid crystal display panels. Regarding

[0002]

2. Description of the Related Art Conventionally, this type of packing (gasket)
For example, Japanese Patent Laid-Open No. 2001-100216 is known. The publication introduces a packing mainly composed of a foamed body having elasticity and a density of 300 to 500 kg / m ³ and a resin film having rigidity, which is intended to seal a liquid crystal display panel of a mobile phone. ing.

However, this is mainly for the purpose of 1) dustproof, 2) prevention of light leakage of the backlight, and 3) prevention of rattling, and it is insufficient in terms of airtightness and waterproofness. It did not prevent water from entering the inside when it got wet or dropped in a water pool.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above circumstances, and has excellent shape retention and good handling work such as mounting to parts, and also has airtightness and waterproofness. The purpose is to provide excellent packing.

[0005]

According to the present invention, the hardness is JIS
A packing characterized by being obtained by laminating a base material having rigidity on one surface of an elastic sheet having a density of more than 15 to 60, 500 kg / m ³ by an A hardness meter and punching it into a predetermined shape. .

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The packing according to the present invention will be described in more detail below. FIG. 1 shows an example of a packing 1 according to the present invention, and reference numeral 2 in the drawing has a hardness of JIS.
An elastic sheet having an A hardness meter of 15 to 60 and a density exceeding 500 kg / m ³ (hereinafter referred to as an elastic layer)
Indicates. A base material having rigidity on one side of the elastic layer 2.
(Hereinafter, referred to as a rigid layer) 3 is laminated to form a laminated body. This laminated body is punched into a predetermined shape.

The hardness of the elastic layer is J in order to exhibit the adhesion and cushioning property to the mating base material, which is suitable as a packing.
It must be in the range of 15 to 60 on the ISA hardness tester. This is because if the hardness exceeds 60, the adhesion becomes poor, it becomes impossible to sufficiently seal the gap of a complicated shape, and the load on the parts becomes large when the device is assembled, and in some cases, This is because the mating base material may be damaged. Further, when it is less than 15, the compressive stress is too small and the airtight performance and waterproof performance are insufficient.

Further, in order to improve the airtightness and waterproofness of the packing, it is necessary to set the density of the elastic layer constituting the present invention to a range exceeding 500 kg / m ³ . Here, when the density is 500 kg / m ³ or less, the airtight performance and waterproof performance of the elastic layer itself are insufficient.
0 to 1300 kg / m ³ is preferable from the viewpoint of function and industrialization. These two performances tend to increase as the density increases, but at the same time, the hardness increases and the ability to follow complex shapes decreases, so 570-1000 kg /
m ³ is more preferable.

The elastic layer may be either open cells or closed cells as long as it is a foamed resin, but the closed cells are preferable from the viewpoint of exhibiting superior airtightness and waterproofing performance. The elastic layer includes not only a sheet but also an extremely thin sheet-like one called a film.

Examples of the foamed resin include foamed materials such as polyurethane, polyolefin, EPDM, NBR, silicone, vinyl chloride, etc. Among them, polyurethane foam which has few bleed-out components, is inexpensive, and has good processability is used. preferable.

The polyurethane foam can be obtained by various conventional production methods. Examples of this manufacturing method include a one-shot method, a prepolymer method, and a mechanical floss method.

As the polyol used in the production of the polyurethane foam, those generally used can be used without particular limitation, and examples thereof include polyether polyol, polyester polyol and polycarbonate polyol. By selecting a hydrophilic polyol,
It is possible to obtain packing with extremely good waterproof performance. Examples of the hydrophobic polyol include polybutadiene-based polyol, isoprene-based polyol, and dimer acid ester-based polyol.

As the isocyanate compound used in the production of the polyurethane foam, those which are generally used can be used without particular limitation. One or more of aromatic, aliphatic or alicyclic isocyanate compounds such as methane-4,4-diisocyanate and tetramethylxylylene diisocyanate and derivatives thereof can be used.

As the catalyst used for producing the polyurethane foam, generally used tertiary amines and organometallic compounds can be used without particular limitation.
Examples of the tertiary amines include bis (2,2′-dimethylamino) ethyl ether, trimethylamine, triethylamine, N-methylmorpholine, N-ethylmorpholine, N, N-dimethylbenzylamine, N, N-dimethylethanol. Examples thereof include amine, N, N, N ′, N′-tetramethyl-1,3-butanediamine, triethanolamine, 1,4-dihexamethylenetetramine, and pyridine oxide, and the organometallic compound is dibutyltin laurate. , Dibutyltin malate, dilauryltin diacetate, dioctyltin diacetate and the like.

The blowing agent used for producing the polyurethane foam is not particularly limited, and those generally used for producing polyurethane foam can be used. Examples thereof include water, pentane, hexane, cyclopentane, cyclohexane, methylene chloride, and other low boiling point compounds.

As the foam stabilizer used in the production of the polyurethane foam, a commonly used silicone-based surfactant can be used. Particularly, as a functional group capable of chemically bonding with an isocyanate group, a hydroxyl group is used. The waterproof performance can be further improved by using a foam stabilizer having a carboxyl group, an amino group, an epoxy group or the like in its structure.

The elastic layer constituting the present invention is JIS
As long as the A hardness is 60 or less, the material may be a non-foamed resin, and examples thereof include elastomers such as polyurethane and polyolefin resin. Among them, a thermoplastic elastomer is particularly preferable from the viewpoint of laminating processability of the elastic layer and the rigid layer.

The rigid layer that constitutes the present invention may be any layer that can impart rigidity to the elastic layer to improve shape retention, and is, for example, polyethylene terephthalate, polypropylene, polyester, nylon, polystyrene, or polyamide. There is a resin film or sheet.

Besides the resin, a metal sheet may be used. In this case, since the packing is provided with conductivity, static electricity can be prevented. Examples of this metal include aluminum, stainless steel, zinc, copper, and iron, but stainless steel and aluminum are particularly preferable in terms of rust resistance. Further, pulp such as paper can be used, but in this case, it is preferable that the surface treatment is performed to the extent that the waterproof property of the packing is not lost.

The thickness of the rigid layer is appropriately selected according to the purpose of use, but it is preferably 20 to 200 μm, particularly preferably 30 to 100 μm. The reason is that if the thickness is less than 20 μm, the rigidity of the packing becomes insufficient, and if the thickness exceeds 200 μm, the followability of the packing deteriorates. In addition, the particularly preferable range of the thickness is set as described above because it has appropriate rigidity for handling work,
This is because it is a range that also has the ability to follow a complicated shape.

To laminate the elastic layer and the rigid layer,
There is a method of directly coating the raw material on the surface of the rigid layer and integrally molding it at the time of manufacturing the elastic layer, and examples thereof include a doctor knife method, a die coating method, a gravure roll method, and a spray method. Further, as another method, there is a method of adhering products manufactured in separate steps, and examples thereof include a heat laminating method, a bonding laminating method, and a frame laminating method.

However, in the method using an adhesive such as the bonding laminating method, the compound in the adhesive component volatilizes to contaminate the surrounding parts, which may cause malfunction in precision equipment. Not very desirable. Therefore, it is preferable to integrate them by a method that does not use an adhesive. Among them, the heat laminating method is effective, and by using a thermoplastic elastomer as the elastic layer, it becomes possible to easily laminate it with the rigid layer.

The packing according to the present invention is used by adhering it to a target component through an adhesive or a double-sided adhesive tape on the rigid layer. In this attaching work step, the packing can be prevented from being twisted or displaced due to the shape stability provided by the rigid layer.

[0024]

EXAMPLES Examples 1 to 5 of the present invention and comparative examples will be described below. However, the present invention is not limited to these examples. (Materials used) Polyol A: (polyether polyol having a molecular weight of 3000 obtained by addition-polymerizing propylene oxide to glycerin, hydroxyl value 56) Polyol B: (molecular weight obtained by addition-polymerizing propylene oxide to glycerin 4000 polyether polyol, hydroxyl value 42) Polyol C: (trade name of Hitachi Chemical Polymer Co., Ltd .:
Teslac 2458 (dimer acid ester-based polyol, hydroxyl value 74.1) MDI: product name: MR manufactured by Nippon Polyurethane Industry Co., Ltd .: MR
-400 (Polymeric MDI, NCO%: 31) Catalyst A: Trade name: DAB manufactured by Sankyo Air Products Co., Ltd.
CO-33LV (33% dipropylene glycol solution of triethylenediamine) Catalyst B: Nitto Kasei Co., Ltd. product name: Neostan U-2
8 (Stanas dioctoate) Foam stabilizer: Product name: F-303 manufactured by Shin-Etsu Chemical Co., Ltd.
(Polydimethylsiloxane-Polyoxyalkylene Copolymer) In Examples 1 to 4 and Comparative Example 1, urethane raw materials having the formulations shown in Table 1 below were added to a surface of a polyethylene terephthalate film having a thickness of 50 μm to a thickness of 0.5 mm. Sheeting was performed and the reaction was cured.

In Example 5, the elastic layer has a thickness of 0.5 m.
An ethylene / butyl adipate ester-based TPU sheet (density 1110 kg / m ³ , JIS A hardness 55) molded into m was laminated on a polyethylene terephthalate film having a thickness of 50 μm by a heat lamination method.

In Comparative Example 2, the elastic layer has a thickness of 0.5 m.
An adipate ester-based TPU sheet (density 1230 kg / m ³ , JIS A hardness 80) molded to a thickness of 5
It was laminated on a 0 μm polyethylene terephthalate film by a heat lamination method.

The test results of the airtightness and waterproofness of the obtained packings of Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 2 below.

[0028]

[Table 1]

[0029]

[Table 2]

(Measurement Method of Physical Properties) Density: According to JIS K6400. The unit is kg / m ³ . Hardness: Measured with JIS A hardness meter. Airtightness: A double-sided adhesive tape was attached to the polyethylene terephthalate side of the obtained packing, which was then punched into a ring shape and attached to an acrylic plate. Furthermore, after compressing this packing by 20% using another acrylic plate, a pressure of 5000 mmH ₂ O was applied to the inner diameter of the packing to measure the amount of air leaking out (unit: cc / min). did.

FIG. 2 is an explanatory view of an apparatus used for the airtightness (the same applies to the waterproof property) test. The number 11 in the figure is
The packing as a test body is shown. This packing 11 is
It is sandwiched between two acrylic plates 12a and 12b via a spacer 13, and is fixed to 20% compression by a fixing bolt 14. A constant pressure air compressor 16 is connected to the packing 11 via a pipe 15.
A first pressure gauge 17, a flow meter 18, a pressure adjusting valve 19, and a second pressure gauge 20 are sequentially connected to the pipe 15 in order from the constant pressure air compressor 16 side.

Water resistance: A double-sided adhesive tape was attached to the polyethylene terephthalate side of the obtained packing, which was then punched into a ring shape and attached to an acrylic plate. Furthermore, after compressing this packing by 20% using another acrylic plate, the inner diameter of the packing is filled with distilled water and pressure is applied, and the water pressure (mmH ₂ O)
Was measured.

Therefore, the smaller the airtightness, the smaller the leaked air amount (higher airtightness), and the higher the waterproofness, the less water leaked out under higher water pressure (waterproofness). Is high).

From Table 2 above, it can be seen from Example 1 in terms of airtightness.
The values of .about.5 are significantly smaller than those of Comparative Examples 1 and 2, and the values of Examples 1 to 5 are significantly larger than those of Comparative Examples 1 and 2 in terms of waterproofness.
It is clear that Comparative Example 5 is superior to Comparative Examples 1 and 2 in terms of airtightness and waterproofness.

[0035]

As described above in detail, the packing composed of the elastic layer having the predetermined hardness and density according to the present invention has appropriate cushioning property and adhesiveness, Excellent in air tightness and waterproofness. In addition, the presence of the rigid layer stabilizes the shape and facilitates handling.

[Brief description of drawings]

FIG. 1 is a sectional view of a packing according to the present invention.

FIG. 2 is a cross-sectional view of an apparatus used for airtightness and waterproofness tests.

[Explanation of symbols] 1, 11 ... packing, 2 ... sheet (elastic layer), 3 ... Base material (rigid layer), 12a, 12b ... Acrylic plate, 13 ... Spacer, 14 ... Fixing bolt, 15 ... Piping, 16 ... Constant pressure air compressor, 17, 20 ... Pressure gauge, 18 ... Flowmeter, 19 ... Pressure regulating valve.

Claims (5)

[Claims] 1. The hardness of JIS A hardness tester is 15 to 60,
A packing obtained by laminating a base material having rigidity on one side of an elastic sheet having a density exceeding 500 kg / m ³ and punching it into a predetermined shape. 2. The packing according to claim 1, wherein the sheet is made of polyurethane foam. 3. The packing according to claim 1, wherein the sheet is made of a thermoplastic elastomer. 4. The packing according to claim 1, wherein the sheet is a low moisture permeable polyurethane obtained from a hydrophobic polyol as a raw material. 5. The packing according to claim 1, wherein the base material is paper.