JPS59196384A - Sealing medium - Google Patents

Abstract

PURPOSE:To provide a sealing medium having low compressive strength and good elastic recovery after relieving of compressive force and is suitable for automobile window, etc., prepared by forming a covering layer of a sealant all over a skin-covered open cellular plastic foam obtained by foam extrusion molding of a specified resin composition. CONSTITUTION:The sealing medium is prepared by forming a covering layer of a sealant (e.g. butyl rubber) all over a skin-covered open cellular plastic foam obtained by foam extrusion molding of a resin composition consisting of 100pts.wt. olefinic resin (e.g. polyethylene, polypropylene or ethylene/vinyl acetate copolymer), 60-150pts.wt. ionic copolymer (e.g. a copolymer obtained by neutralizing ethylene/methacrylic acid copolymer with Na ion for introduction of an ionic bond) and a foaming agent. The plastic foam has an open cellular structure within but none on the surface which is covered with a skin layer, has low compressive strength and good elastic recovery after relieving of compressive force, is free from penetration of sealant within the foam, has good insertion workability and is suitable for windows of automobiles and buildings.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a sealing material having a structure in which a sealing material layer is formed around a core material, and is suitable for use in automobile windows, building windows, etc. The inside of the foam has an open-cell structure, and the surface of the foam has no communicating holes and has a skin, has low compressive strength, and has good resilience after release of compressive force, and has a good resistance to the inside of the foam. The present invention relates to a sole hoist with good insertion workability using a skinned open-cell foam as a core material without the penetration of sealant.

Conventionally, as a sealing material having a structure in which a sealing material layer is formed around a core material, a resin material having a spongy structure as a core material or a pipe material as shown in Japanese Patent Publication No. 52-39654 has been used. A construction material polymerization part that uses a string-like tensile resistor made of rubber or synthetic resin with elasticity and is coated with a sealing material layer mainly made of adhesive butyl-based synthetic rubber on the surrounding surface. It is known whether the seal used in the publication is. However, when the outer diameter of the sealing material is relatively small (approximately 5 inches), for example when it is used around the window glass of a car, the compressive strength of the core material of the above sealing material is too high, and the insertion process becomes difficult. It was bad sex. In addition, when the core material has a sponge-like structure, the sealing material penetrates into the interior of the core material, resulting in an increase in compressive strength and a disadvantage that a large amount of sealing material is consumed, resulting in high cost. Furthermore, depending on the type of core material, such as rubber, there are some that are corroded by the sealant and have durability problems.

In view of the above-mentioned points, the present invention focuses on the fact that the above-mentioned problems can be solved by using a skinned open-cell foam as a core material, which has a low compressive strength and is not corroded by sealants or penetrated by sealants. It has been done.

Conventionally, as a manufacturing method for open-cell foam, for example, as disclosed in Japanese Patent Publication No. 5.1-944, 70 to 99% by weight of polyolefin and 1 to 30% by weight of styrene polymer were used.
A known method is to extrude a foamable mixed polymer composition containing 0.1 to 0.5% by weight of a thermally decomposable chemical blowing agent based on the weight of the mixed polymer. However, although the foams produced by these methods have an open cell structure, there are communicating pores extending to the surface, making them breathable. In addition, when making a foam using a crystalline olefin resin, when the temperature of the olefin resin reaches a temperature higher than its melting point, the melt viscosity of the olefin resin decreases rapidly, and the temperature range in which it exhibits viscoelasticity suitable for foaming is extremely narrow. ,
It was difficult to produce a uniform foam.

In order to improve this manufacturing method,
34226, a resin component consisting of 100 parts by weight of a crystalline polyolefin and 2 to 50 parts by weight of an ionic copolymer is mixed with a volatile organic blowing agent and extruded to form a foam with a density of 0.035 g/cc or less. A method for forming a density homogeneous microcellular structure is presented. However, this method forms a homogeneous fine cell structure of closed cells, and it is not possible to produce a product having an open cell structure with a skin.

Moreover, the temperature range suitable for foaming was still narrow, and the foamed products had high compressive strength, poor recovery properties after release of compressive force, and low tensile strength at break.

The object of the present invention is to use a core material that has low compressive strength, has good resilience after release of compressive force, does not allow sealing material to enter into the core material, and is not attacked by the sealant, and seals around this core material. The purpose of the present invention is to provide a sealing material with good insertion workability by providing a material layer.

That is, the gist of the present invention is to extrude and foam a resin composition in which 60 to 150 parts by weight of an ionic copolymer and a blowing agent are mixed with 100 parts by weight of an olefin resin, and around an open-cell foam with a skin, A sealing material characterized by being coated with a sealing material layer.

The olefin resins used in the present invention include polymers of olefin monomers such as low density polyethylene, medium density polyethylene, high density polyethylene, linear image, density polyethylene 1/7, polypropylene, and ethylene-propylene copolymer. Coalescence, ethylene-vinyl acetate copolymer, ethylene-
Copolymers mainly composed of olefin R-mers such as vinyl chloride copolymers and ethylene-ethyl acrylate copolymers, and copolymers mainly composed of olefin-based carmers such as propylene-ethylene-1-butene copolymers. It refers to terpolymers, modified polyolefins such as chlorinated polyethylene, and mixtures of these polymers.

The olefin resins include low density polyethylene, linear low density polyethylene, high density polyethylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, and ethylene, in view of the viscosity characteristics of the ionic copolymer. - Ethyl acrylate copolymers and other materials with relatively low melting points are preferably used, and those with melting points in the range of 100 to 140° C. are particularly preferred. The melting index is M I 0.
5 to 30 g/l and 0 minutes are preferred.

The ionic copolymer used in the present invention is a copolymer of α-olefin such as ethylene, propylene, butene-1, etc. and a polymerizable unsaturated carbonic acid.
It is a copolymer that has been neutralized with metal ions such as a, Zn, Cu, etc., or organic bases such as amines, and has ionic crosslinks introduced therein. As the above polymerizable unsaturated carboxylic acid, acrylic acid, methacrylic acid, maleic acid, etc. can be used. The proportion of the polymerizable unsaturated carboxylic acid in the ionic copolymer is preferably 0.2 to 25 mol%, particularly preferably 1 to 10 mol%. The ionic copolymer preferably has a melting index of MI' of 0.5 to 30 g/10 min.

In the present invention, a foam is produced from a resin composition consisting of a mixture of the above-mentioned olefin resin, an ionic copolymer, and a blowing agent, or a mixture of the above-mentioned mixture with additives such as a coloring agent. .

In the present invention, the above olefin resin 100
A resin composition containing 60 to 150 parts by weight of the ionic copolymer is used. If the ionic copolymer is less than 60 parts by weight, the suitable temperature range for foaming open cells will be narrow and it will be impossible to stably form open cell foams, and the foam will become closed cells and the compressive strength will decrease. If the ionic copolymer
If the amount exceeds 50 parts by weight, the kneading properties, extrudability, etc. will not be stable, and a uniform skinned open-cell foam will not be obtained.If 60 to 150 parts by weight of the ionic copolymer is mixed, extrusion The surface tension of the outer surface of the resin during foaming has a sufficient viscosity to prevent outgassing, and the appropriate extrusion temperature range is widened, and a uniform resin film is formed on the outer surface, while the inside of the resin contains the foaming agent. Even with the heat of vaporization, etc., the bubbles are not cooled enough to crystallize, and the bubbles are uniformly destroyed.
As a result, a uniform and stable skinned open-cell foam is obtained.

As a method for manufacturing the open-cell foam, a method similar to the conventionally known extrusion foaming method can be used. For example, a blowing agent is blended into the above resin composition, and the mixture is kneaded and melted using an extruder or the like at high temperature and high pressure to achieve an appropriate viscosity (temperature, pressure).
Alternatively, the resin composition is kneaded and melted in an extruder, a foaming agent is injected midway through the extruder, kneaded further, and extruded and foamed under moderate viscosity conditions. For example, the method of

Examples of blowing agents include gases such as nitrogen gas and carbon dioxide gas, hydrocarbons such as pentane and butane, and volatile organic blowing agents such as halogenated hydrocarbons such as dichlorodifluoromethane and 1,2-dichlorotetrafluoroethane, and heating. A chemical blowing agent such as azobisisobutyronitrile, which decomposes and generates gas, is used. In particular, volatile organic blowing agents are preferred since they can produce foams with high magnification.

In extrusion foaming, in addition to the above-mentioned foaming agents, a cell nucleating agent such as an inorganic powder such as talc or a gas generating agent such as bicarbonate may be used as a cell control agent for the foam.

Furthermore, it is preferable to stretch the foam that comes out of the extruder during extrusion foaming, as this further improves the tensile strength of the foam.

Furthermore, when the foam is stretched, the outer diameter of the foam can be easily controlled. The stretching ratio is preferably 1.5 times or more, particularly preferably 2 to 6 times.

The density of the skinned open-cell foam used in the present invention is preferably in the range of 0.02 to 0.2 g/ca as it has an appropriate compressive strength as the core material of the sealing material, and is particularly preferably in the range of 0.03 to 0.0 g/ca. .1 g/cl. If the density is too low and the expansion ratio is too high, it will be difficult to produce a uniform skinned open-cell foam and the compression recovery properties will be poor; if the density is too high and the expansion ratio is too low, It becomes difficult to form open cells and the compressive strength becomes large.

In addition, the resin composition of the present invention may contain heat stabilizers, antioxidants, fillers, etc., as long as they do not interfere with foamability, physical properties, etc.
Plasticizers, flame retardants, colorants, antistatic agents, etc. can be added.

In the present invention, as shown in FIG. 1, a skinned open-cell foam 1 manufactured by the above method is used as a core material, and a sealing material layer 2 is formed around this core material to form a sealing material. That is to say.

The skinned open-cell foam 1 has a thin skin 11 with
It has a structure in which a large number of bubbles 12 are communicated in the axial direction of the foam 1, and when compressed, the air inside the foam flows into the bubbles 1.
The bubbles are discharged through the bubbles 12 and have low compressive strength, and when the compressive force is dissolved, air enters the bubbles 12 and restores them to their original shape.

Acknowledgment: The compressive strength of the material is 1°2br at 75% compression.
15 cm (length 5 cm0) sample is compressed at a compression speed of 10 mm 1 minute) or less, especially 0.5 kg 1
5 cm or less is preferable. The tensile strength of the core material is 5,
It is preferably 0 kg/cut (pulling speed 200 mm Z) or more, particularly preferably 7.0 kg/cl+ or more.

The sealing material is one that has adhesive properties and can adhere to objects and seal between objects, such as those mainly made of butyl rubber such as butyl rubber, halogenated butyl, recycled butyl, cross-linked butyl, etc. It will be done. Furthermore, organic additives such as polyisobutylene, asphalt, and phthalate esters, and inorganic substances such as calcium carbonate and silicic anhydride may be added to the above-mentioned butyl rubber to adjust the viscosity, adhesiveness, etc.

Next, as one mode of use of the seal shrine of the present invention, an example in which it is used in an automobile window will be described with reference to FIG. 2.

FIG. 2 is a cross-sectional view of the lower part of an automobile hack window, in which rubber gaskets 1 to 3 are installed around the glass 1.
This is attached to the window frame of the car's Hoti 5. In this case, the sealing material is inserted into the glass groove of the rubber gasket 3 to seal between the rubber gasket 3 and the glass 4. At this time, if the compressive strength of the sealing material is small, the workability of inserting the sealing material into the glass groove of the rubber gasket 3 is improved (and the workability of installing the ring-shaped rubber gasket 3 onto the glass 4 is also improved. In this case, Seal Io is also used between the rubber gasket 3 and the body 5. At this time, if the compressive strength of the sealing material is small, it becomes easier to attach the glass to the window frame of the body 5.

The sealing material of the present invention has an open-cell foam with a skin formed by extruding and foaming a resin composition in which 60 to 150 parts by weight of an ionic copolymer and a blowing agent are mixed with 1.0 parts by weight of an olefin resin as a core material. Because of the use of ionic copolymers, the suitable temperature range for foaming open cells is expanded, and open cell foams with skins can be easily and stably produced, and the produced foams have low compressive strength. The core material has good resilience after release of compressive force, high tensile strength (tensile strength), and has an excellent skin that prevents the sealant from penetrating into the core material and prevents the sealant layer from being attacked. Since a sealing material layer is formed around this core material, it has excellent durability as a whole and has low compressive strength.
It has high tensile strength and excellent insertion workability.

Furthermore, since the core material has a high tensile strength, the productivity of the coating work when coating a sealant such as butylcomb is high, and the manufacturing cost of the sealant is low.

Therefore, the sealing material of the present invention has a low compressive strength, and
Applications that require good resilience and tensile strength after release of compressive force, especially applications that require small outer diameters, such as automotive window sealing materials, building window sealing materials, and between panels. It is preferably used for sealing materials for filling, joints, etc.

The present invention will be explained below with reference to Examples.

Example density: 0.927 g/cra, melting point: 117°C, softening point: 1"Vicat) 96°C, M14.5g/10 min. density 0°95 (1/cnt, Melting point 96°C1 Softening point 72'C, M
110g/10 minutes of ionic copolymer 70 parts by weight and 20.6 parts by weight of the ionic copolymer were mixed, fed to an extruder with a diameter of 50+=m, melted and kneaded, and passed through a starter tube installed near the tip of the extruder. 1,2-cyclothiol-1-rafluoroethane was press-injected into one package injection, kneaded and gelled, extruded into the atmosphere through a nostle, and foamed into a round rod shape with a diameter of 3.3 am while being stretched to about 4 g. Molded.

The 1M foam had a density of 0.055g/c and the first
As shown in the figure, it had a skin, and the inside had many cells or continuous cells in the axial direction. When this foam was pinched and pressed between fingers, it collapsed easily, and when the pressing force was released, it immediately returned to its original state. Table 1 shows the physical properties of this skinned open cell foam.

This skinned open-cell foam is used as a core material, and around it, 55% by weight of butyl rubber and 34% by weight of polyisobutylene are used.
A sealing material consisting of 3% by weight of phthalate ester and 8% by weight of silicic acid anhydride was coated to prepare a sealing material having an outer diameter of 5 fins as shown in FIG. 2. The physical properties of this sealing material are also shown in Table 1.

Comparative Example 100 parts by weight of the low-density polyethylene used in the example was mixed with 0.6 parts by weight of talc, and using an extruder with a diameter of 50 mm, a round bar with a diameter of 3.3 mm was prepared in the same manner as in the example. A foam was produced.

The obtained foam had a density of 0.050 g/cJ and was a closed-cell foam. When this foam was pinched and pressed between fingers, it was elastic and required force to press, and even after the pressing force was released, it took a long time to recover. The physical properties of this foam are also shown in Table 1.

This foam was used as a core material, and a sealing material having the same composition as in the example was coated around the foam to create a sealing material with an outer diameter of 5 ++ ua. The physical properties of this sealing material are also shown in Table 1.

Table 1 It can be seen from Table 1 that the sealing material of the present invention has low compressive strength and good insertion workability.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the sealing material of the present invention. FIG. 2 is a sectional view showing one mode of use of the sealing material of the present invention. 1... Open-cell foam with skin, 2...
・Sealing + A layer. Patent applicant Sekisui Chemical Co., Ltd. Representative Motoshi Fujinuma

Claims (1)

[Claims] 1. Forming a sealing layer around an open-cell foam with a skin formed by extruding and foaming a resin composition in which 60 to 150 parts by weight of an ionic copolymer and a blowing agent are mixed with 100 parts by weight of an olefin resin. A sealing material that is characterized by: