Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J9/00—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof
  • C08J9/04—Working-up of macromolecular substances to porous or cellular articles or materials; After-treatment thereof using blowing gases generated by a previously added blowing agent
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L101/00—Compositions of unspecified macromolecular compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2323/00—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers
  • C08J2323/02—Characterised by the use of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Derivatives of such polymers not modified by chemical after treatment

Definitions

• the present invention relates to a polyolefin resin foam and a polyolefin resin foam dustproof material using the same.
• a resin foam containing a polystyrene resin or a polyolefin resin as a resin component is widely used as a cushioning material for packaging, a structural member for automobiles, etc. because of its various characteristics.
• a dustproof material made of a resin foam containing a polyolefin-based resin as a resin component has attracted great attention because it is excellent in cushioning properties, dust resistance, moldability and the like.
• Patent Document 1 discloses a thermoplastic polymer which is a mixture of an olefin elastomer and an olefin polymer other than the olefin elastomer, and the mixing ratio (by weight) of the mixture is 20/80 to 80/20 in the former / the latter.
• the pressure reduction step is carried out, and the average cell diameter is 10 to 90 ⁇ m.
• a dustproof material made of foam having characteristics of 1 to 3.0 N / cm 2 and an apparent density of 0.01 to 0.10 g / cm 3 .
• Patent Document 2 describes a dustproof material composed of a foam having a thickness of 0.1 to 1.0 mm, wherein the foam has a fine cell structure having an average cell diameter of 10 to 65 ⁇ m, 0.1 mm.
• a foam dustproof material having characteristics such that the repulsive load when compressed to a thickness is 0.010 to 0.100 MPa, and an apparent density of 0.01 to 0.050 g / cm 3 .
• the dustproof material disclosed in Patent Document 1 is too soft and inferior in handling property (handling property), has poor ability to follow fine gaps and steps, and has the ability to prevent the entry of dust and water. There is a problem that it is inadequate.
• the dustproof material disclosed in Patent Document 2 is a foamed dustproof material having a fine cell structure, the dustproof material is too soft to be handled easily. Further, there is a problem that the repulsive load in the case of high compression is large, the followability becomes insufficient, and the followability to a minute gap or a step is inferior.
• the foam dustproof materials described in Patent Documents 1 and 2 can easily be used. There is a problem that the foam dustproof material tries to be restored in the thickness direction by long-term use even if the follow-up ability is insufficient because it can not be crushed and the follow-up ability is sufficient, and the long-term reliability is lacking. The Therefore, the present inventors can easily crush (following ability) with a low load and prevent intrusion of dust, water and the like from fine gaps and steps by using a resin foam having specific physical properties. And it discovered that the dustproof material which maintained shape and a dustproof and waterproof performance also by long-term use can be obtained, and came to complete this invention.
• the thickness 0.1 ⁇ 3.0 mm, an average cell diameter 0.02 ⁇ 0.2 mm, an apparent density of 30 ⁇ 100kg / m 3, Compressive stress at 50% compression is over 15 KPa, If it is a polyolefin resin foam having a compressive stress of 400 KPa or less when compressed by 80%, when it is used as a dustproof material, it has excellent handling properties (handling properties) and is easily crushed with a low load (following properties), It has been found that it is a dustproof material that can prevent dust, water, and the like from entering through fine gaps and steps for a long time.
• the foamed structure of the polyolefin resin foam of the present invention is an open cell structure, it is possible to provide a dustproof material further excellent in followability, dimensional stability and long-term stability.
• the present invention has a thickness of 0.1 to 3.0 mm, an average cell diameter of 0.02 to 0.2 mm, and an apparent density of 30 to 100 kg / m 3 , Compressive stress at 50% compression is over 15 KPa, It is a polyolefin resin foam characterized in that the compression stress at the time of 80% compression is 400 KPa or less. Moreover, it is a foaming dustproof material using the said polyolefin-type resin foam.
• the polyolefin-based resin foam of the present invention has a small average cell diameter and an appropriate strength according to the above configuration, and therefore, when used as a dustproof material, it is excellent in handling properties, such as dust and water from fine gaps and steps. It is a foam dustproof material that prevents intrusion and has excellent follow-up ability to be easily crushed with a low load.
• the polyolefin resin foam of the present invention has a long-term dustproof property when used as a dustproof material, for example, because the change over time is small (the dimensional accuracy is good) even when the resin is highly compressed. It becomes a thing.
• the foamed structure of the polyolefin resin foam of the present invention is an open cell structure, it can be more easily crushed with a low load, and the apparent magnification can be made into a non-foamed state. Therefore, while maintaining high dust resistance, the shape change with time is small, and the dimensional stability is more excellent.
• the present invention has a thickness of 0.1 to 3.0 mm, an average cell diameter of 0.02 to 0.2 mm, and an apparent density of 30 to 100 kg / m 3 , Compressive stress at 50% compression is over 15 KPa, It is a polyolefin resin foam characterized in that the compression stress at the time of 80% compression is 400 KPa or less.
• the polyolefin resin foam of the present invention has a lower limit of 0.1 mm and an upper limit of 3.0 mm in thickness.
• the thickness is less than 0.1 mm, the strength of the polyolefin resin foam is insufficient, and the handling property is deteriorated.
• the thickness exceeds 3.0 mm, the compressive stress of the polyolefin resin foam becomes too large, and the followability deteriorates, and when it is used as a dustproof material, the intrusion of dust, water, etc. from fine gaps or steps is caused. It can not be prevented.
• the preferred lower limit of the thickness is 0.2 mm, and the preferred upper limit is 1.5 mm. In addition, in order to adjust to the range of the said thickness, you may process by a slice etc. suitably.
• the lower limit of the average cell diameter is 0.02 mm and the upper limit is 0.2 mm.
• the average cell diameter is less than 0.02 mm, the strength of the polyolefin resin foam is insufficient, and the handling property is deteriorated.
• the average bubble diameter exceeds 0.2 mm, the followability deteriorates, and when it is used as a dustproof material, it is not possible to prevent the entry of dust, water, etc. from fine gaps or steps.
• the preferred lower limit of the average cell diameter is 0.04 mm, and the preferred upper limit is 0.15 mm.
• the lower limit of the apparent density of the polyolefin resin foam of the present invention is 30 kg / m 3 and the upper limit thereof is 100 kg / m 3 .
• the apparent density is less than 30 kg / m 3 , the strength of the polyolefin resin foam is insufficient, and the handling property is deteriorated.
• the apparent density exceeds 100 kg / m 3 , the compressive stress of the polyolefin resin foam becomes too large, and the followability deteriorates, and when used as a dustproof material, dust, water, etc. from fine gaps or steps are produced. It will not be possible to prevent the intrusion.
• the preferable lower limit of the apparent density is 35 kg / m 3
• the preferable upper limit is 90 kg / m 3
• the more preferable lower limit is 40 kg / m 3
• the more preferable upper limit is 70 kg / m 3 .
• the lower limit of the compressive stress at the time of 50% compression is 15 KPa.
• the preferred lower limit of the compressive stress at 50% compression is 35 KPa, and the more preferred lower limit is 40 KPa.
• the upper limit of the compressive stress at 50% compression is not particularly limited, but from the viewpoint of followability, it is preferably 100 KPa or less, more preferably 90 KPa or less, and still more preferably 80 KPa or less .
• the upper limit of the compressive stress at the time of 80% compression is 400 KPa in the polyolefin resin foam of the present invention. If the compression stress at the time of 80% compression exceeds 400 KPa, it can not be easily compressed, the repulsive force becomes strong and the followability deteriorates, and when it is used as a dustproof material, fine gaps and It becomes impossible to prevent the intrusion of dust, water, etc. from the step.
• the upper limit of the compressive stress at the time of 80% compression is preferably 380 KPa, and more preferably 350 KPa.
• the lower limit of the compressive stress at the time of 80% compression is not particularly limited, but from the viewpoint of sealability, it is preferably 100 KPa or more, more preferably 150 KPa or more, and still more preferably 180 KPa or more .
• the foam structure of the polyolefin resin foam of the present invention is preferably an open cell structure.
• the open cell structure means one having an open cell ratio of 60% or more measured by a measurement method described later.
• the open cell ratio is 60% or more, it is easily crushed with a low load, and the dimensional change is small with long-term use, and the shape can be maintained, so dust and water from fine gaps and steps for a long time Etc. can be prevented.
• it is 65% or more, More preferably, it is 70% or more.
• the surface hardness of the polyolefin resin foam of the present invention is not particularly limited, but the preferable lower limit is 50, and the preferable upper limit is 100. If the surface hardness is less than 50, the followability can not be maintained, and when used as a dustproof material, it may not be possible to prevent the entry of dust, water, etc. from fine gaps or steps with time. If the surface hardness exceeds 100, it can not be easily compressed, the repulsive force becomes strong and the followability deteriorates, and when used as a dustproof material, it is possible to prevent the intrusion of dust, water, etc. from fine gaps and steps. It may not be possible.
• the more preferable lower limit of the surface hardness is 55, the more preferable upper limit is 95, the still more preferable lower limit is 60, and the still more preferable upper limit is 90.
• the polyolefin resin foam of the present invention having the above respective physical properties has, for example, a polyolefin resin having a melting point in the range of 140 to 180 ° C. and a deflection temperature under load of 80 to 140 ° C. It can be produced by extrusion foaming of a mixed resin composition containing a thermoplastic elastomer having a softening point of 45 to 160 ° C.
• the production method will be described in detail, but the present invention is not limited to the production method.
• the preferable lower limit of the melting point of the polyolefin resin is 140 ° C., and the preferable upper limit is 180 ° C.
• the melting point of the polyolefin resin is less than 140 ° C.
• the dimensional stability may be poor when used under a high temperature environment. Specifically, when used as a dustproof material, the foam may be deformed due to high temperature, and the ability to follow fine clearances may be poor.
• the melting point of the polyolefin-based resin exceeds 180 ° C., it is necessary to knead the resin at a high temperature, and in addition to causing the thermal deterioration of the polyolefin-based resin, the physical properties of other added resins may be significantly reduced.
• the more preferable lower limit of the melting point of the polyolefin resin is 155 ° C., and the more preferable upper limit is 170 ° C.
• the preferable lower limit of the deflection temperature under load of the polyolefin resin is 80 ° C., and the preferable upper limit is 140 ° C.
• the deflection temperature under load of the polyolefin resin is less than 80 ° C.
• the dimensional stability when used under a high temperature environment may be inferior.
• the foam may be deformed due to high temperature, and the ability to follow fine clearances may be poor.
• the deflection temperature under load of the polyolefin resin exceeds 140 ° C., it is necessary to knead the resin at a high temperature, so in addition to causing the thermal deterioration of the polyolefin resin itself, the physical properties of other added resins are significantly reduced.
• the more preferable lower limit of the deflection temperature under load of the polyolefin resin is 90 ° C.
• the more preferable upper limit is 130 ° C.
• the melt flow rate (MFR) of the polyolefin resin is not particularly limited, but the preferable lower limit is 0.2 g / 10 min, and the preferable upper limit is 5 g / 10 min.
• MFR melt flow rate
• the MFR of the above-mentioned polyolefin resin is less than 0.2 g / 10 min, the load on the extruder is increased, the productivity is lowered, or the molten polyolefin resin containing a foaming agent smoothly in the mold. It becomes impossible to flow, and unevenness may occur on the surface of the resulting polyolefin resin foam, which may reduce the appearance.
• the resin pressure in front of the annular die decreases, and the resin pressure in the annular die bubble generating portion also decreases, so that bubbles are generated in front of the bubble generating portion
• the foamability may be lowered due to the rapid formation of foam in the foam-formed portion, the appearance of the obtained polyolefin resin foam may be lowered, or the polyolefin resin foam may not be obtained.
• the lower limit of the MFR of the polyolefin resin is more preferably 0.25 g / 10 min, still more preferably 4 g / 10 min, still more preferably 0.3 g / 10 min, still more preferably 3.5 g / 10 min.
• MFR of polyolefin resin refers to what was measured by the test temperature of 230 degreeC, and 21.18 N of test loads based on B method of JISK 7210: 1999.
• MFR of polyolefin resin refers to what measured MFR of the resin by the said method, when polyolefin resin is used individually by 1 type.
• the MFR of each individual polyolefin resin is measured by the above-mentioned measuring method, and calculated from the value of each MFR as follows. .
• MFR of the polyolefin resin 1 is MFR 1
• MFR of the polyolefin resin 2 is MFR 2
• the content of the polyolefin resin 1 is C1
• the content of the polyolefin resin 2 is C2,...
• the content of the polyolefin resin n is Cn.
• the content of the polyolefin resin n is obtained by dividing the weight of the polyolefin resin n by the weight of the entire polyolefin resin.
• the polyolefin-based resin is not particularly limited as long as it has the above-mentioned physical properties, and specific examples thereof include homopolypropylene, a copolymer of propylene and another olefin, and the like.
• the copolymer of propylene and another olefin may be either a random copolymer or a block copolymer, but a block copolymer is preferable because it is excellent in heat resistance.
• Other olefins copolymerized with propylene include, for example, 1-butene, 1-pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, etc. in addition to ethylene.
• ⁇ -olefins having 4 to 10 carbon atoms are preferable, and homopolypropylene which is excellent in heat resistance is more preferable.
• the melt tension polypropylene resin it is preferable to use high melt tension polypropylene resin from it being excellent in foamability.
• the melt tension can be increased by including high melt tension polypropylene (HMS-PP) having free long-end long-chain branches in the molecular structure by electron beam crosslinking or the like, and high molecular weight components.
• HMS-PP high melt tension polypropylene
• a commercially available product can be used as the high melt tension polypropylene, and specific examples thereof include trade name “Newstoren SH9000” manufactured by Japan Polypropylene Corp., trade name “DaployWB135HMS” manufactured by Borealis, and the like.
• the said polyolefin resin may be used independently, and 2 or more types may be used together.
• the preferable lower limit of the melting point of the thermoplastic elastomer is 140 ° C.
• the preferable upper limit is 180 ° C.
• the melting point of the thermoplastic elastomer is less than 140 ° C.
• the dimensional stability when used in a high temperature environment may be poor.
• the foam when used as a dustproof material, the foam may be deformed due to high temperature, and the ability to follow fine clearances may be poor.
• thermoplastic elastomer If the melting point of the thermoplastic elastomer exceeds 180 ° C., it is necessary to knead the resin at a high temperature, and in addition to causing thermal deterioration of the thermoplastic elastomer itself, the physical properties of other polyolefin resins or added resins are significantly reduced. There is something I can do.
• a more preferable lower limit of the melting point of the thermoplastic elastomer is 150 ° C., and a more preferable upper limit is 170 ° C.
• the preferable lower limit of the softening point of the thermoplastic elastomer is 45 ° C., and the preferable upper limit is 160 ° C. If the softening point of the thermoplastic elastomer is less than 45 ° C., the dimensional stability may be poor when used in a high temperature environment. Specifically, when used as a dustproof material, the foam may be deformed due to high temperature, and the ability to follow fine clearances may be poor.
• thermoplastic elastomer If the softening point of the thermoplastic elastomer exceeds 160 ° C., it is necessary to knead the resin at a high temperature, and in addition to causing thermal degradation of the thermoplastic elastomer itself, the physical properties of other polyolefin resins or added resins are significantly increased. May decrease.
• a more preferable lower limit of the softening point of the thermoplastic elastomer is 70 ° C., and a more preferable upper limit is 150 ° C.
• the melt flow rate (MFR) of the thermoplastic elastomer is not particularly limited, but the preferable lower limit is 0.1 g / 10 min, and the preferable upper limit is 20 g / 10 min.
• MFR melt flow rate
• the MFR of the thermoplastic elastomer is less than 0.1 g / 10 min, the load on the extruder is increased, the productivity is reduced, or the molten thermoplastic elastomer containing a foaming agent smoothly in the mold. It becomes impossible to flow, and unevenness may occur on the surface of the resulting polyolefin resin foam, which may reduce the appearance.
• the MFR of the thermoplastic elastomer exceeds 20 g / 10 min, the resin pressure in front of the annular die decreases, and the resin pressure in the annular die bubble-generating portion also decreases, so bubbles are generated in front of the bubble-generating portion As a result, the foamability may be lowered due to the rapid formation of foam in the foam-formed portion, the appearance of the obtained polyolefin resin foam may be lowered, or the polyolefin resin foam may not be obtained.
• a more preferable lower limit of MFR of the thermoplastic elastomer is 0.2 g / 10 min, and a more preferable upper limit is 15 g / 10 min.
• the hardness of the thermoplastic elastomer is not particularly limited, but is preferably 90 or less in terms of Duro A hardness specified by JIS K6253, from the viewpoint of obtaining a polyolefin resin foam having excellent flexibility. More preferably, it is about 80.
• the thermoplastic elastomer has a structure in which a hard segment and a soft segment are combined, exhibits rubber elasticity at normal temperature, and has a property of being plasticized and able to be molded like a thermoplastic resin at high temperature.
• the hard segment is a polyolefin resin such as polypropylene or polyethylene
• the soft segment is a rubber component such as ethylene-propylene-diene copolymer or ethylene-propylene copolymer or non-crystalline polyethylene.
• thermoplastic elastomer a polymerization type elastomer which is directly produced in a polymerization reaction vessel by conducting polymerization of a monomer to be a hard segment and a monomer to be a soft segment in multiple steps; kneading such as Banbury mixer or twin screw extruder Type elastomer produced by physically dispersing a polyolefin-based resin to be a hard segment and a rubber component to be a soft segment using a mechanical press; hard using a kneader such as a Banbury mixer or twin-screw extruder By adding a crosslinking agent when physically dispersing the polyolefin resin to be a segment and the rubber component to be a soft segment, the rubber component is completely crosslinked or partially crosslinked and microdispersed in the polyolefin resin matrix. Dynamically Crosslinked Elastomer Obtained And the like.
• the present invention it is possible to use both the non-crosslinked elastomer and the crosslinked elastomer, and when using the non-crosslinked elastomer produced by physically dispersing the rubber component to be the soft segment, the manufactured product is recycled.
• the same extrusion molding as that for extrusion molding of a normal polyolefin resin is possible, and the foam molding is recycled and supplied again to the extruder for the same foam molding. Even in this case, foaming defects and the like due to the crosslinked rubber can be suppressed.
• a crosslinked elastomer obtained by partially dispersing or dynamically crosslinking the rubber component is used at the same time as physically dispersing the rubber component to be a soft segment, it is possible to obtain excellent compatibility with the polyolefin resin, It is preferable because the heat resistance of the foam is enhanced.
• the diene component constituting the ethylene-propylene-diene copolymer elastomer include ethylidene norbornene, 1,4-hexadiene, dicyclopentadiene and the like.
• the ethylene-propylene-diene copolymer elastomer may be used alone or in combination of two or more, and by using such an ethylene-propylene-diene copolymer elastomer, a common polyolefin can be used. It becomes easy to manufacture with the same extruder as the case of extrusion-foaming molding of the base resin.
• the melt flow rate (MFR) of the mixed resin composition is not particularly limited, but the preferable lower limit is 0.1 g / 10 min, and the preferable upper limit is 3 g / 10 min. If the MFR of the mixed resin composition is less than 0.1 g / 10 min, the load on the extruder becomes large, the productivity is lowered, and the molten polyolefin resin containing a foaming agent smoothly in the mold. It becomes impossible to flow, and a corrugate may generate
• the MFR of the mixed resin composition exceeds 3 g / 10 min, when an annular die is used as a mold, the resin pressure in front of the annular die decreases, and the resin pressure in the annular die bubble forming portion also decreases. Thus, bubbles are generated in front of the bubble-generating portion, and the foamability is sharply generated in the foam-forming portion, whereby the foamability is reduced, the appearance of the obtained polyolefin resin foam is lowered, or the polyolefin resin There is a possibility that the foam can not be obtained.
• the more preferable lower limit of the MFR of the mixed resin composition is 0.2 g / 10 min, and the more preferable upper limit is 2.5 g / 10 min.
• the ratio of the polyolefin resin to the thermoplastic elastomer in the mixed resin composition is not particularly limited, but it is preferably in the range of 20:80 to 80:20 by mass ratio. If the content of the thermoplastic elastomer is less than this range, the buffer properties and flexibility of the resulting polyolefin resin foam may be poor. When the content of the thermoplastic elastomer is more than this range, the rubber elasticity of the mixed resin composition becomes too strong, the foamability may be reduced, or the shrinkage of the obtained polyolefin resin foam may be increased.
• a more preferable range of the ratio of the polyolefin resin and the thermoplastic elastomer is 40:60 to 60:40.
• Air bubble nucleating agent When producing the polyolefin resin foam of this invention, it is preferable to use a cell nucleating agent.
• the cell nucleating agent promotes the formation of cell nuclei when the polyolefin resin foaming composition forms the cells, and has an effect on the miniaturization and uniformity of the cells.
• the cell nucleating agent examples include talc, mica, silica, diatomaceous earth, alumina, titanium oxide, zinc oxide, magnesium oxide, magnesium hydroxide, aluminum hydroxide, calcium hydroxide, potassium carbonate, calcium carbonate, magnesium carbonate, sulfuric acid
• Inorganic compounds such as potassium, barium sulfate, sodium hydrogencarbonate and glass beads
• organic compounds such as polytetrafluoroethylene, azodicarbonamide, a mixture of sodium hydrogencarbonate and citric acid, and inert gases such as nitrogen.
• talc is preferred as the inorganic compound
• polytetrafluoroethylene is preferred as the organic compound, because the effect of refining the cells is high. Further, it is particularly preferable that the melt tension of the resin is increased by the fibrillar form of polytetrafluoroethylene when dispersed.
• the amount of the cell nucleating agent is not particularly limited, but a preferable lower limit is 0.01 parts by weight and a preferable upper limit is 15 parts by weight with respect to 100 parts by weight of the mixed resin composition.
• a preferable lower limit is 0.01 parts by weight and a preferable upper limit is 15 parts by weight with respect to 100 parts by weight of the mixed resin composition.
• the amount of the cell nucleating agent is less than 0.01 parts by weight, it is difficult to increase the number of cells of the obtained polyolefin resin foam, and the surface smoothness of the obtained polyolefin resin foam is lowered. There is.
• the amount of the cell nucleating agent exceeds 15 parts by weight, secondary aggregation is likely to occur, and the surface smoothness of the foam due to extrusion foam failure may be reduced.
• a more preferable lower limit of the amount of the cell nucleating agent is 0.1 parts by weight, and a more preferable upper limit is 12 parts by weight.
• the cell nucleating agent used in the present invention may be mixed with the mixed resin composition in the form of itself or may be fed separately into the extruder. Moreover, you may mix with a mixed resin composition as a masterbatch, and may supply separately in an extruder.
• the base resin of the master batch is not particularly limited as long as it is excellent in compatibility with the mixed resin composition, and preferably used is, for example, homopolypropylene, block polypropylene, random polypropylene, low density polyethylene, high density polyethylene, etc. can do.
• various additives generally used for foam molding can be added to the polyolefin resin foaming composition used in the present invention as an optional component.
• the additive include weather resistant stabilizers, light stabilizers, pigments, dyes, flame retardants, crystal nucleating agents, plasticizers, lubricants, surfactants, dispersants, ultraviolet light absorbers, antioxidants, and fillers. , Reinforcing agents, antistatic agents and the like. Among these, surfactants impart slip and antiblocking properties.
• a dispersing agent improves the dispersibility of an inorganic filler, for example, a higher fatty acid, a higher fatty acid ester, a higher fatty acid amide etc. are mentioned.
• the addition amount of the additive can be appropriately selected within a range that does not impair the formation of air bubbles, the physical properties of the resulting foam, and the like, and the addition amount used for molding of a general thermoplastic resin can be adopted.
• the above additives can also be used as a master batch in order to facilitate the handling and to prevent the contamination of the production environment due to powder scattering and to improve the dispersibility in the thermoplastic resin.
• the masterbatch can be usually carried out by kneading additives or the like at a high concentration into a thermoplastic base resin to form pellets.
• the base resin is not particularly limited as long as it is excellent in compatibility with the mixed resin composition, and preferably used is, for example, homopolypropylene, block polypropylene, random polypropylene, low density polyethylene, high density polyethylene, etc. Can.
• Foaming agent As the foaming agent, known foaming agents that can be used for extrusion foam molding can be used. A physical blowing agent supplied by being pressed into the extruder is preferable because the expansion ratio can be easily adjusted. In the present invention, it is particularly preferable to use carbon dioxide. By using carbon dioxide in a supercritical state, a subcritical state or liquefied carbon dioxide, it is possible to form finer cells than conventional foams, and the surface smoothness of the resulting polyolefin resin foam is obtained. And flexibility can be improved.
• the amount of the foaming agent to be pressed into the extruder may be appropriately adjusted according to the expansion ratio of the polyolefin resin foam, but if it is small, the expansion ratio of the polyolefin resin foam becomes low, and the lightness and weight While heat insulation may decrease, if it is too much, foaming may occur in the mold to cause foam breakage or large voids may occur in the polyolefin resin foam, so for polyolefin resin foaming
• the amount is preferably about 1 to 10 parts by weight, more preferably about 2 to 8 parts by weight, and particularly preferably about 3 to 6 parts by weight with respect to 100 parts by weight of the composition.
• any extruder of single-screw extruder, twin-screw extruder, and tandem extruder can be used as an extruder.
• a tandem extruder is preferable because the extrusion conditions can be easily adjusted.
• the mold used in the above manufacturing method has an annular ring having a bubble generating portion formed by squeezing the resin flow path, and a foam forming portion for growing the generated bubbles and smoothing the surface of the foam. Composed of dies. Since the polyolefin resin foam of the present invention has finer cells than in the past, when foamed using a conventional ring die, a large number of corrugations are generated on the surface of the foam and are obtained. The surface smoothness of the foam is deteriorated. However, the annular die included in the foam-formed portion can suppress the occurrence of the corrugation in the bubble-formed portion by the appropriate sliding resistance in the foam-formed portion, and can obtain a foam having a smooth surface.
• corrugated as used herein means a number of ridges and valleys that can be produced by waving the foam from the annular die in order to absorb the amount of linear expansion in the circumferential direction due to volume expansion.
• the discharge velocity V of the resin in the bubble generation portion be 50 to 300 kg / cm 2 ⁇ hr and the resin pressure before the annular die be 7 MPa or more.
• the discharge speed V is more preferably about 70 to 250 kg / cm 2 ⁇ hr, and further preferably about 100 to 200 kg / cm 2 ⁇ hr.
• the resin pressure in front of the annular die is preferably 7 MPa or more, and more preferably 8 MPa or more and 20 MPa or less.
• the processability in the case of carrying out secondary processing of the obtained foam improves, and the sheet-like foam obtained by slicing is obtained with excellent surface smoothness.
• the discharge speed V is less than about 50 kg / cm 2 ⁇ hr, it may be difficult to obtain finer foams and foams having a high expansion ratio.
• the resin generates heat in the mold bubble generation part to cause cell breakage, and the foaming ratio tends to be reduced, and additionally, a corrugated corrugated sheet tends to be generated to cause cell formation. Since the diameter becomes uneven and the surface smoothness of the foam is lowered, it is not preferable.
• the discharge speed V is appropriately adjusted by the cross-sectional area of the annular die bubble generation part and the extrusion discharge amount.
• the resin pressure in front of the annular die is lower than 7 MPa, bubble generation starts in front of the annular die bubble-generating portion, which is not preferable because a good foam can not be obtained. If the pressure is higher than 20 MPa, the load on the extruder may be too high, or the injection pressure of the foaming agent may be too high to be able to press-in, which is not preferable.
• the resin pressure in front of the annular die is appropriately adjusted according to the molten resin viscosity and the extrusion discharge amount, and the sectional area of the annular die bubble generation portion. Further, the viscosity of the molten resin is appropriately adjusted by the viscosity of the blended resin composition, the amount of the foaming agent added, and the temperature of the molten resin.
• the molten resin temperature in this specification refers to the temperature measured by a thermocouple attached in direct contact with the molten resin in a straight pipe mold for measuring the resin pressure in front of the annular die. say.
• the foamed dustproof material (foamed sealing material) of the present invention is composed of a polyolefin resin foam having the above-mentioned specific characteristics.
• the foam dustproof material effectively exhibits its function even in the form of a foam alone, the foam dustproof material having a form in which an adhesive layer is provided on one side or both sides of the foam is preferred and easy to use.
• surface or both surfaces of a foam it can fix to the to-be-adhered body which needs dustproof, and can be temporarily fixed.
• the pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer is not particularly limited, and, for example, acrylic pressure-sensitive adhesives, rubber-based pressure-sensitive adhesives (natural rubber-based pressure-sensitive adhesives, synthetic rubber-based pressure-sensitive adhesives, etc.), silicone-based pressure-sensitive adhesives, polyester-based pressure-sensitive adhesives
• Known pressure-sensitive adhesives such as urethane-based pressure-sensitive adhesives, polyamide-based pressure-sensitive adhesives, epoxy-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives and fluorine-based pressure-sensitive adhesives can be appropriately selected and used.
• the pressure-sensitive adhesive may be used alone or in combination of two or more.
• the pressure-sensitive adhesive may be any form of pressure-sensitive adhesive such as an emulsion-based pressure-sensitive adhesive, a solvent-based pressure-sensitive adhesive, an oligomer-based pressure-sensitive adhesive, and a solid-based pressure-sensitive adhesive.
• a pressure-sensitive adhesive an acrylic pressure-sensitive adhesive is preferable from the viewpoint of preventing contamination of an adherend, and the like.
• the adhesive layer can be formed using a known forming method. For example, after a pressure-sensitive adhesive is applied to form a pressure-sensitive adhesive layer on a release film such as a method (coating method) of applying a pressure-sensitive adhesive on a predetermined site or surface or a release liner, the pressure-sensitive adhesive layer is Or the method (transfer method) etc. which are transferred on a surface are mentioned.
• coating method The casting method, the roll coater method, the reverse coater method, the doctor blade method etc.
• coating method The casting method, the roll coater method, the reverse coater method, the doctor blade method etc.
• the thickness of the adhesive layer is usually about 5 to 100 ⁇ m. The thinner the adhesion layer, the higher the effect of preventing the adhesion of dust and dirt at the end, so the thinner the better.
• the adhesive layer is formed only on one side (one side) of the foam
• another layer may be formed on the other side of the foam, for example, another type of adhesion Layer etc. are mentioned.
• the shape, thickness and the like of the foamed dustproof material of the present invention are not particularly limited, and can be appropriately selected according to the application and the like.
• the thickness of the foam dustproof material can be selected from the range of about 0.1 to 3 mm (preferably 0.3 to 2 mm).
• processing such as a punching process, is normally made in various shapes according to the apparatus used, and it is commercialized.
• the foamed dustproof material of the present invention has the above-mentioned characteristics, so it is easy to apply, hardly changes in thickness with time, and is excellent in sealability, dimensional accuracy, and dimensional stability.
• the average cell diameter of the polyolefin resin foam refers to one measured in the following manner in accordance with the test method of ASTM D2842-69. Specifically, the foam sheet is cut along the MD direction (extrusion direction) and the TD direction (direction orthogonal to the extrusion direction), and the central portion of each cut surface is a scanning electron microscope (manufactured by Hitachi, Ltd.) S-3000N) was enlarged and photographed. Next, the photographed image is printed on A4 paper, and one straight line of 60 mm in length is drawn on the image.
• the cut surface cut in the MD direction is parallel to the MD direction
• the cut surface cut in the TD direction is parallel to the TD direction
• the VD direction thickness direction
• sheet Draw a straight line sheet Draw a straight line
• the magnification of the above electron microscope was adjusted so that there were about 10 to 20 bubbles on a 60 mm straight line.
• the average chord length (t) of the bubbles was calculated from the number of bubbles present on the straight line according to the following equation, and this average chord length was taken as the average bubble diameter in each direction (MD direction, TD direction and VD direction).
• Average chord length t 60 / (number of bubbles ⁇ magnification of the photo)
• the straight line in drawing a straight line, it is made for the straight line to be in the penetrated state without being in point contact with air bubbles as much as possible.
• the bubbles are included in the number of bubbles, and both ends of the straight line are positioned in the bubbles without penetrating the bubbles.
• the number of bubbles also includes the bubbles at which both ends of the straight line are located.
• the bubble diameter is calculated by the following equation based on the average chord length t calculated by the above equation.
• the compressive stress of the polyolefin resin foam is measured by the method according to JIS K 6767 foamed plastic-polyethylene-test method. Specifically, the compression stress is measured when the sample cut into 50 mm ⁇ 50 mm is compressed at 1 mm / min.
• a measuring device Tensilon universal testing machine UCT-10T manufactured by Orientec Co., Ltd. can be used. The thickness tested is about 2 mm.
• Open cell rate ⁇ Apparent volume-Actual volume (measured value) ⁇ ⁇ Apparent volume ⁇ 100
• Mitomerics dry-type automatic densimeter Accupyc II 1340 (V1.0) made by Shimadzu Corporation can be used.
• the measurement of the surface hardness of the polyolefin resin foam refers to the measurement as follows. Specifically, a flat smooth sample cut into 50 mm squares is stacked on a thickness of about 6 mm or more, the pressure surface of the meter is pressed against the surface of the horizontally placed sample, and the memory after loading a 1 kg weight is read.
• Asker rubber hardness meter CSC2 manufactured by Kobunshi Keiki Co., Ltd. is used.
• the melting point refers to a value measured in the following manner in accordance with JIS K 7121 plastic transition temperature measurement method. Specifically, heating and cooling rate: 10 C./min, measurement start / end temperature: -40 ° C. to 220.
• a differential scanning calorimeter (DSC) manufactured by SII Nanotechnology Inc., model number DSC6220 is used.
• ⁇ MFR> MFR means the value measured as follows according to the flow test method of JIS K 7210 thermoplastics. Specifically, measurement is performed at a test temperature of 230 ° C., a test load of 21.18 N, and a preheating time of 5 minutes. As a measuring device, a semi-automatic melt indexer manufactured by Toyo Seiki Seisaku-sho, Ltd. is used.
• Deflection temperature under load means the value measured according to JIS K7191 B method.
• the softening point refers to a value measured in the following manner in accordance with the method of measuring the softening temperature by thermal mechanical analysis (TMA) of JIS K 7196 thermoplastic plastic films and sheets. Specifically, the measurement is performed with a test piece size: 1010 ⁇ 1 (mm), a temperature rising rate: 5 ° C./min, a measurement mode: needle insertion test mode (tip ⁇ 1 mm), and a load: 500 mN.
• TMA thermal mechanical analysis
• IP code refers to a value measured in the following manner in accordance with the method of measuring the IP code according to the protection grade (IP code) according to the outline of JIS C0920 electric machine equipment. Specifically, those that are protected against the intrusion of foreign solids 1.0 mm or more in diameter and that are not adversely affected by water by spray water within 60 degrees from the vertical are IP 43, diameter 1.0 mm or more IP44 protected against the ingress of foreign solids and not adversely affected by splashes from any direction. Even if there is some dust intrusion, it does not disturb normal operation, and it is IP57 that is not adversely affected even if it is immersed in water under a specified pressure and time.
• ⁇ Convexity followability> A 200 mm ⁇ 200 mm square, 10 mm thick acrylic plate was used, in which an uneven surface having a height of 1 mm was uniformly present at intervals of 5 mm on one side. Two pieces of the above-mentioned acrylic plate were used so as to be superposed so that the uneven surface was overlapped, and a foam of 100 mm ⁇ 100 mm square was sandwiched therebetween so as to be uniform, and the four corners were fixed. Thereafter, the foam was compressed 50% with respect to the thickness, and the followability to unevenness of 1 mm height in the compressed state was visually observed.
• Example 1 A tandem-type extruder was prepared by connecting a second extruder having a diameter of 75 mm to a tip of a first extruder having a diameter of 65 mm. Non-crosslinked ethylene was added to 60 parts by weight of a polyolefin resin (E110G manufactured by Prime Polymer Co., melting point: 161 ° C., deflection temperature under load: 115 ° C., MFR: 0.3 g / 10 min) in the first extruder of this tandem type extruder.
• a polyolefin resin E110G manufactured by Prime Polymer Co., melting point: 161 ° C., deflection temperature under load: 115 ° C., MFR: 0.3 g / 10 min
• thermoplastic elastomer thermolan Z101N manufactured by Mitsubishi Chemical Corp., melting point: 170 ° C., softening point: 142 ° C., MFR: 11 g / 10 min
• a polyolefin resin foamable composition was prepared by mixing 10 parts by weight of a masterbatch containing 70% by weight of talc having an average particle diameter of 12 ⁇ m as a cell nucleating agent in a first portion and melt kneading it.
• the air bubble generation part diameter ⁇ 36 mm of the mold attached to the tip of the second extruder, the air bubble generation part interval of the mold 0.25 mm (cross section of the air bubble generation part: 0.275 cm 2 ) Discharge amount 30 kg / hr (discharge speed V 109 kg / cm 2 ⁇ hr) from a ring die having a diameter of 70 mm at an outlet diameter of 3.4 mm and a foam forming part, resin temperature 175 ° C., resin pressure in front of the ring die 9.
• a cylindrical foam molded in the foam molding portion of the annular die is attached onto a cooled mandrel, and the outer surface is cooled and molded by blowing air from an air ring.
• a cylindrical foam was cut with a cutter to obtain a sheet-like polyolefin resin foam as described in Table 1.
• the polyolefin resin foam obtained by the above method has no occurrence of corrugate and is excellent in surface smoothness, and hence is excellent in secondary processability such as slicing.
• a mixed resin composition in which a polyolefin resin and a thermoplastic elastomer are mixed in the above ratio is melt-kneaded at 200 ° C. with an extruder and maintained at 200 ° C. (extruder, mold temperature After extruding in a strand form at 200 ° C., the mixture was water-cooled to obtain a mixed resin composition (a resin composition for extrusion and foaming) molded into a cylindrical pellet. As a result of measuring a melt flow rate about the obtained mixed resin composition, it was 0.7 g / 10 min.
• Example 2 Both surfaces of the polyolefin resin foam obtained in Example 1 were sliced by a splitting machine to remove the skin and obtain a sheet-like polyolefin resin foam as shown in Table 1 after slicing.
• Example 3 Similar to Example 1 except that the polyolefin resin was changed to E-100 GV (melting point: 161 ° C., deflection temperature under load: 120 ° C., MFR: 0.5 g / 10 min) manufactured by Prime Polymer Co., Ltd. 4.2 parts by weight of carbon was injected, and extrusion foaming was performed under the conditions of a resin temperature of 175 ° C. and a resin pressure of 10.2 MPa in front of the annular die, to obtain a sheet-like polyolefin resin foam shown in Table 1. The melt flow rate of the mixed resin composition was measured in the same manner as in Example 1 and found to be 1.3 g / 10 min.
• Example 4 Both sides of the polyolefin resin foam obtained in Example 3 were sliced by a splitting machine to remove the skin and obtain a sheet-like polyolefin resin foam as shown in Table 1 after slicing.
• Example 5 The carbon dioxide in the supercritical state is 4.2 in the same manner as in Example 1 except that the thermoplastic elastomer is changed to Notio (melting point: 154 ° C., softening point: 100 ° C., MFR: 7 g / 10 min) manufactured by Mitsui Chemicals, Inc.
• the parts were pressed in by weight, and extrusion foaming was performed under the conditions of a resin temperature of 180 ° C. and a resin pressure of 10.0 MPa in front of the annular die to obtain a sheet-like polyolefin resin foam as described in Table 1.
• the melt flow rate of the mixed resin composition was measured in the same manner as in Example 1 and found to be 0.5 g / 10 min.
• Comparative Example 1 A sheet-like foam ("Heat cell” manufactured by Sekisui Plastics Co., Ltd.) described in Table 1 of modified polyphenylene oxide which is a commercially available engineering plastic was used.
• Comparative Example 2 The sheet-like closed-cell foam (Sekisui Chemical Co., Ltd. "Softlon") of Table 1 which irradiated the electron beam to polyethylene marketed was used.
• Comparative Example 3 A sheet-like foam ("Poron SR-S15P” manufactured by Inoac Co., Ltd.), which is a commercially available urethane foam, is used.
• Comparative Example 4 A sheet-like foam (Pef, manufactured by Toray Industries, Inc.) described in Table 1 which is a commercially available, semi-rigid, closed-cell, polyolefin foam by electron beam crosslinking was used.
• the compressive stress at the time of 50% compression is 15 KPa or more
• the compressive stress at the time of 80% compression is the open cell structure of 400 KPa or less If it is a sheet-like polyolefin resin foam, the handling property (handling property) is excellent, the load is easily crushed at a low load (following property), the dimensional accuracy is good, and the long-term stability of the seal is excellent.
• the polyolefin resin foam of the present invention is suitably used in the field of dustproof materials.
• the polyolefin resin foam of the present invention can be suitably used in fields requiring flexibility and followability, electronic devices requiring sealing property and dust resistance, home appliances, housing and automobiles, and the like.
• the foamed dustproof material of the present invention can be suitably used in electronic equipment, household appliances, housing, automobiles and the like for which sealing properties, dustproofness, dimensional accuracy are required.

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• 2012
  • 2012-03-26 JP JP2013507553A patent/JP5938395B2/ja not_active Expired - Fee Related
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  • 2012-03-26 WO PCT/JP2012/057721 patent/WO2012133288A1/ja active Application Filing
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