JP6318570B2 - Polyolefin resin foam film and laminated film - Google Patents

Description

  The present invention relates to a polyolefin resin foam film and a laminated film excellent in heat insulation and strength.

  Foamed resin films are used in various places where light weight, heat insulation, and sound insulation are required. For example, building materials are used for flooring, wall materials, doors, window frames and the like, and are used for the purpose of sound insulation, heat insulation, vibration isolation, and the like.

  As a conventional method for producing a foamed resin film, a method is disclosed in which a chemical foaming agent is added to a base polystyrene resin, polyethylene resin or polyurethane resin, and the foaming agent is chemically foamed simultaneously with molding. However, the chemical foaming method has a problem that it is difficult to control the degree of foaming and it is difficult to form a uniform foamed shape. In particular, when the thickness of the film is reduced, it is difficult to produce a stable foamed film, such that the accuracy of the thickness becomes unstable and the production becomes more difficult.

  As means for solving the above-mentioned problem, Patent Document 1 (Japanese Patent Laid-Open No. 9-226073) provides a cavity by stretching a laminated sheet having a crystalline polypropylene resin as a surface layer, and stacks two or more films. A method for producing a sheet having a cavity by heat bonding is proposed. However, this method requires a process of heat-welding a plurality of stretched sheets, so that there are many production steps, the productivity is inferior, and it is difficult to provide sufficient heat insulation performance.

  Patent Document 2 (WO2013 / 100015A) proposes a method for producing a polyolefin resin foam sheet by melt-kneading a polyolefin resin composition in a extruder together with a supercritical carbon dioxide gas as a foaming agent. Has been. However, since this method uses carbon dioxide gas in a critical state, there is a problem that costs associated therewith, such as equipment that handles high-pressure gas and an explosion-proof wall around the equipment, are involved, and costs increase. . Further, the present situation is that the strength of the obtained sheet is not sufficiently satisfactory.

Japanese Patent Laid-Open No. 9-226073 WO2013 / 100015A

  An object of this invention is to provide the polyolefin resin foam film and laminated | multilayer film excellent in heat insulation and intensity | strength, without requiring big capital investment.

That is, the present invention
[1] A polyolefin-based resin (A) and a thermal expansion microcapsule (B) are contained, and the thermal expansion microcapsule (B) has a temperature at which expansion starts at 100 to 155 ° C. and a maximum expansion temperature. Is a polyolefin-based resin foam film, characterized by being 160 to 230 ° C.
[2] The mass ratio of the polyolefin resin (A) and the thermal expansion microcapsule (B) is (A) :( B) = 97-80: 3-20, Polyolefin resin foam film.
[3] The polyolefin resin foam film according to [1] or [2], wherein the tensile strength (MD) is 2.0 MPa or more.
[4] The polyolefin resin foam film according to any one of [1] to [3], further comprising titanium oxide.
[5] A laminated film having the polyolefin resin foam film according to any one of [1] to [4].
[6] The laminated film according to [5], having the polyolefin resin foam film as an intermediate layer.
[7] The laminated film according to [5] or [6], wherein the layer on the surface of the laminated film does not contain a thermal expansion microcapsule.
Is provided.

  According to the present invention, it is possible to provide a polyolefin-based resin foam film and a laminated film having performances excellent in heat insulation and strength.

  Below, the polyolefin-type resin foam film and laminated | multilayer film of this invention are demonstrated in detail.

  The polyolefin-based resin foam film of the present invention contains a polyolefin-based resin (A) and a thermal expansion microcapsule (B), and the thermal expansion microcapsule (B) has a temperature at which expansion starts to be 100 to 155 ° C. It is important that the maximum expansion temperature is 160 to 230 ° C.

<Thermal expansion microcapsule>
The thermal expansion microcapsule used in the present invention has a temperature at which expansion starts from 100 to 155 ° C, preferably from 110 to 155 ° C, and more preferably from 130 to 155 ° C.
By setting the temperature at which the expansion starts to 100 ° C. or more, when molding using a polyolefin resin, the thermal expansion microcapsule hardly expands immediately after the resin is put into an extrusion molding machine, so that stable molding is possible. Can be possible. Moreover, the temperature which starts expansion | swelling shall be 155 degrees C or less, and the temperature which this thermal expansion microcapsule begins to expand in a nozzle | cap | die becomes moderate in the molding temperature of the polyolefin resin to be used.

The thermal expansion microcapsule used in the present invention has a maximum expansion temperature of 160 to 230 ° C, preferably 160 to 220 ° C, and more preferably 160 to 210 ° C.
By setting the maximum expansion temperature to 160 ° C. or higher, appropriate expansion can be obtained at the timing before and after being discharged from the molding machine. In addition, by setting the maximum expansion temperature to 230 ° C. or less, the temperature at which the thermally expanded microcapsules expand to the maximum at the molding temperature of the polyolefin resin to be used becomes appropriate, and an efficient foamed state can be obtained.

In the thermal expansion microcapsule used in the present invention, the mass ratio of the polyolefin resin (A) and the thermal expansion microcapsule (B) is preferably (A) :( B) = 97-80: 3-20. 95 to 85: 5 to 15 is more preferable, and 93 to 87: 7 to 13 is more preferable.
By making the mass ratio of the polyolefin-based resin (A) and the thermal expansion microcapsule (B) in the above range, the film can be foamed properly and the heat insulation performance can be improved. High strength can be maintained.

  In the case where the thermal expansion microcapsule (B) is contained in the polyolefin resin (A) and molded, the thermal expansion microcapsule (B) is previously added in order to prevent scattering of the thermal expansion microcapsule (B) and improve dispersibility. You may use what was mixed with other resin and made into a masterbatch. As the masterbatch resin used in this, an ethylene-vinyl acetate copolymer (EVA) is preferable from the viewpoint of compatibility with the polyolefin resin.

  As the thermal expansion microcapsule (B) used in the present invention, there are Daiichi Seika Kogyo Co., Ltd .: Die Foam, Matsumoto Yushi Co., Ltd .: Matsumoto Microsphere, Akzo Nobel Co., Ltd .: EXPANCEL.

<Polyolefin resin>
Examples of the polyolefin resin used in the present invention include polyethylene resins, polypropylene resins, and mixtures thereof.

Polyethylene resins include ethylene homopolymers and / or copolymers of ethylene and other monomers copolymerizable with ethylene (low density polyethylene (LDPE), linear low Density polyethylene (LLDPE), high density polyethylene (HDPE), polyethylene obtained by polymerization using a metallocene catalyst, etc.) or a mixture of the homopolymer and / or copolymer with other copolymer ( Polymer blend) and the like. Examples of polymers that can be mixed with the homopolymer and / or copolymer to give a polymer blend include isoprene rubber, butadiene rubber, butyl rubber, propylene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-isoprene rubber, and the like. diene rubbers, ethylene - propylene nonconjugated diene rubber, an ethylene - polyolefin thermoplastic elastomers such as butadiene copolymer rubber.

  Examples of the polypropylene resin include a propylene homopolymer, a copolymer, or a mixture (polymer blend) of the homopolymer and / or the copolymer with another polymer. Examples of the copolymer include a random copolymer or block copolymer of propylene and ethylene or another α-olefin, or a propylene graft copolymer using a polyolefin-based copolymer as a backbone polymer. . Among these, a random copolymer is preferable because the transparency and flexibility of the film are improved. The α-olefin copolymerizable with propylene preferably has 4 to 12 carbon atoms. For example, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 4-methyl. -1-pentene, 1-decene and the like can be mentioned, and one or a mixture of two or more thereof is used. The mixing ratio of the α-olefin is preferably 1 to 10% by mass, particularly 2 to 6% by mass with respect to propylene.

Examples of the polyolefin copolymer for the backbone polymer of the above-mentioned propylene graft copolymer include ethylene-propylene rubber, ethylene-butene rubber, and ethylene-propylene-diene rubber.
Polymers that can be mixed with propylene homopolymers and / or copolymers to give polymer blends include, for example, isoprene rubber, butadiene rubber, butyl rubber, propylene-butadiene rubber, acrylonitrile-butadiene rubber, acrylonitrile-isoprene. and diene rubber such as rubber, ethylene - propylene copolymer rubber, ethylene - propylene nonconjugated diene rubber, ethylene - include polyolefin-based thermoplastic elastomers such as butadiene copolymer rubber.

  In the polyolefin resin foam film of the present invention, it is particularly preferable to use a polyethylene homopolymer or a mixture of a polyethylene homopolymer and a thermoplastic elastomer. The mixing ratio of the polyethylene homopolymer and the thermoplastic elastomer is preferably 100: 0 to 20:80, and more preferably 100: 0 to 30:70.

  The melt tension of the polyethylene homopolymer used for the polyolefin resin foam film of the present invention is preferably 0.003 to 0.03 N (230 ° C., take-up speed 5 to 50 m / min). If the melt tension is 0.003 N or more, it is easy to mold and a smooth film is easily obtained. If the melt tension is 0.03 N or less, the melt tension will not be too low, and the film will not be difficult to mold. In particular, when molding is performed using a polyethylene homopolymer, a suitable foaming state is obtained because the molding temperature suitably matches the expansion start temperature and / or maximum expansion temperature range of the thermal expansion microcapsule used in the present invention. In addition, it is possible to suppress the occurrence of burning of the thermally expanded microcapsules.

  The polyolefin resin foam film of the present invention preferably has a tensile strength (MD) of 2.0 MPa or more, more preferably 2.5 MPa or more, and further preferably 3.0 MPa or more. By using a tensile strength of 2.0 MPa or more, when used for flooring or wall materials that are building materials, for example, when a polyolefin resin foam film is attached to plywood, the film is prevented from being torn. can do. Further, the upper limit of the tensile strength is not particularly limited, but when pasted on a plywood or the like, if the strength is too high, the handling property may be deteriorated, and therefore it is preferably 25 MPa or less.

  In the present invention, the tensile strength refers to the tensile strength calculated from the point of maximum strength performed in accordance with JIS K7127. When the maximum point is the yield point, it is the tensile strength at the yield point. When the maximum point is the breaking point, it means the tensile strength at the breaking point. MD means the winding direction of the machine when producing a film.

The density of the polyolefin resin foam film of the present invention is preferably 0.30 to 0.70 g / cm ³ . By setting the density of the polyolefin resin foamed film to 0.30 g / cm ³ or more, it is possible to suppress a decrease in strength of the film. Moreover, the heat insulation performance of a film can be made favorable by the density of a polyolefin-type resin foam film being 0.70 g / cm < ³ > or less.

λ：熱伝導率（Ｗ／ｍ・Ｋ）
α：熱拡散率（ＪＩＳ Ｒ１６１１（２０１０）に準拠して測定した。）
Ｃｐ：比熱容量（ＪＩＳ Ｋ７１２３（２０１２）に準拠して測定した。）
ρ：見かけ密度（ＪＩＳ Ｋ７２２２（２００５）に準拠して測定した。） The polyolefin resin foam film of the present invention preferably has a thermal conductivity of 0.1 W / m · K or less. Here, the thermal conductivity can be calculated by the equation (1) by measuring the thermal diffusivity, specific heat capacity, and apparent density of the foamed film.

λ: Thermal conductivity (W / m · K)
α: Thermal diffusivity (measured in accordance with JIS R1611 (2010))
Cp: specific heat capacity (measured in accordance with JIS K7123 (2012))
ρ: Apparent density (measured according to JIS K7222 (2005))

  The polyolefin resin foam film of the present invention preferably contains titanium oxide. By containing titanium oxide in the polyolefin resin foam film, an effect of shielding near infrared rays can be obtained. Thereby, heat insulation performance improves, for example, the temperature rise in object space can be suppressed more, and a synergistic effect with heat insulation performance can be brought about.

  The polyolefin-based resin foam film of the present invention may contain known additives such as stabilizers, lubricants, antistatic agents, weathering aids, and the like as necessary within the range not impairing the effects of the present invention.

  The method for producing the polyolefin-based resin foam film of the present invention is not particularly limited, and a known molding method such as a T-die extrusion molding method or an inflation molding method can be used.

The thickness of the polyolefin resin foam film of the present invention is not particularly limited, but can be set as appropriate depending on the intended use. In general, the thickness is preferably 5 mm or less. Particularly, the polyolefin resin foam film of the present invention can be suitably used when the thickness is 1 mm or less.
The polyolefin resin foam film of the present invention may be a single layer or a multilayer.

  Another embodiment of the present invention is a laminated film including the polyolefin resin foamed film of the present invention, and more preferably a laminated film having the polyolefin resin foamed film of the present invention as an intermediate layer.

  A polyolefin resin foam film may be used as an intermediate layer, and a polyolefin film or other resin may be used to form a laminated film. For example, a polyolefin resin layer can be provided on the surface layer and / or the back layer of the polyolefin resin foam film.

  The polyolefin resin foam film of the present invention suppresses defects in appearance due to foaming by providing a polyolefin resin layer on the surface layer, for example, when used for applications that require excellent performance on the film surface. can do.

In addition, by providing a polyolefin resin layer on the surface layer and / or back layer of a polyolefin resin foam film, it is possible to suppress the mess that adheres to the lip portion of the die that occurs during film production, resulting in good productivity. It can be.
In this case, it is preferable that the surface layer and / or the back layer of the laminated film does not contain a thermally expanded microcapsule. Note that “not containing thermally expanded microcapsules” includes containing a very small amount that does not impair the appearance due to the foaming action of thermally expanded microcapsules.

  The polyolefin resin foam film of the present invention may be subjected to corona discharge treatment on one side and / or both sides as necessary, or a primer layer may be formed.

  The polyolefin-based resin foam film of the present invention may be provided with another resin layer according to weather resistance and other necessary purposes. This resin layer can be formed by laminating or coating a polyolefin resin, a polyester resin, an acrylic resin, a urethane resin, or the like. Further, this resin layer can be embossed.

As a manufacturing method of the polyolefin resin foam film and laminated film of the present invention, (1) a polyolefin resin foam film and other film layers are prepared in advance, and then the polyolefin resin foam film and other film layers are laminated. And (2) a method of directly forming a polyolefin resin foam film and other film layers.
In the case of the method (1), an extrusion laminating method in which a polyolefin resin foam film and other film layers are extruded and laminated by a pressure roll can be used.
In the case of the method (2), the polyolefin resin foam film and other film layers can be prepared by an extrusion method such as a T-die extrusion method, a molding method such as an inflation method and a calendar method. In the present invention, an extrusion molding method is preferably used.

  In the present invention, a general method can be used as a method of kneading the resin in producing the polyolefin-based resin foam film and other film layers. Specifically, pellets, powders, solid strips, etc. are dry-mixed with a Henschel mixer or ribbon mixer, and then mixed into a known melt kneader such as a single or twin screw extruder, Banbury mixer, kneader, or mixing roll. It can be supplied and melt kneaded.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

<Examples 1-7, Comparative Examples 1-3>
<Production of polyolefin resin foam film>
Using the formulations shown in Tables 1 and 2, using a T-die extruder (T-die: 650 mm width) consisting of one 50 mmφ extruder and two 35 mmφ extruders, the die temperature is 180 ° C. A single-layer or three-layer polyolefin-based resin foam film having a thickness of 200 to 900 μm was prepared.
In addition, the ratio of each layer in the case of three layers was produced by surface layer: intermediate layer: back layer = 5: 90: 5.

λ：熱伝導率（Ｗ／ｍ・Ｋ）
α：熱拡散率（ＪＩＳ Ｒ１６１１（２０１０）に準拠して測定した。）
Ｃｐ：比熱容量（ＪＩＳ Ｋ７１２３（２０１２）に準拠して測定した。）
ρ：見かけ密度（ＪＩＳ Ｋ７２２２（２００５）に準拠して測定した。） <Evaluation method>
<Measurement of thermal conductivity>
Using the obtained film, the thermal diffusivity, the specific heat capacity, and the apparent density were measured, respectively, and the thermal conductivity was calculated by the equation (1).
Tables 1 and 2 show the measurement results.

λ: Thermal conductivity (W / m · K)
α: Thermal diffusivity (measured in accordance with JIS R1611 (2010))
Cp: specific heat capacity (measured in accordance with JIS K7123 (2012))
ρ: Apparent density (measured according to JIS K7222 (2005))

<Measurement of tensile strength>
Using the obtained film, the measurement was carried out under the conditions of using a dumbbell having a width of 10 mm at a measurement portion of 23 mm and a chuck distance of 40 mm and a pulling speed of 300 mm / min in accordance with JIS K7127.
Tables 1 and 2 show the measurement results.

<Materials used>
[Polyolefin resin]
(A) -1: Low density polyethylene (manufactured by Nippon Polyethylene Co., Ltd .: LC500)
(A) -2: Polypropylene (manufactured by Nippon Polypro Co., Ltd .: FX3B)

[Thermal expansion microcapsule]
(B) -1: 950DU80 (manufactured by Akzo Nobel: thermal expansion start temperature 138 to 148 ° C, maximum expansion temperature 188 to 200 ° C)
(B) -2: 980DU120 (manufactured by Akzo Nobel: thermal expansion start temperature 158 to 173 ° C, maximum expansion temperature 215 to 235 ° C)
[Titanium oxide]
(C) -1: Titanium oxide (Ishihara Sangyo Co., Ltd.)

なお、実施例６において、酸化チタン（Ｃ）−１は中間層に添加し、その質量部は、ポリオレフィン系樹脂（Ａ）と熱膨張マイクロカプセル（Ｂ）の合計を１００とした時の質量部である。

In Example 6, titanium oxide (C) -1 was added to the intermediate layer, and its mass part was 100 parts by mass when the total of the polyolefin resin (A) and the thermal expansion microcapsule (B) was 100. It is.

<Evaluation results>
From Table 1, it was confirmed that the single-layer films of Examples 1 and 2 and the three-layer films of Examples 3 to 7 all have low thermal conductivity, heat insulation properties, and excellent strength.
On the other hand, from Table 2, it was confirmed that Comparative Example 1 did not contain the thermal expansion microcapsule (B) but contained titanium oxide (C), and as a result, the thermal conductivity was high and the heat insulation performance was inferior. In addition, it was confirmed that Comparative Examples 2 and 3 were inferior in the degree of expansion and inferior in heat insulation performance because the expansion of the thermally expanded microcapsule was not appropriate.
From this result, the polyolefin-based resin foam film and laminated film of the present invention have excellent heat insulating performance of 0.1 W / m · K or less even though the film thickness is thinner than 1 mm, It is also excellent in strength.

Claims (7)

A polyolefin-based resin foam film containing a polyolefin- based resin (A) and a thermal expansion microcapsule (B), wherein the polyolefin-based resin (A) comprises a polyethylene-based resin, a polypropylene-based resin, or a mixture thereof, The thermal expansion microcapsule (B) has a temperature for starting expansion of 130 to 155 ° C., a temperature of maximum expansion of 160 to 230 ° C., and a thermal conductivity of the film of 0.1 W / m · A polyolefin-based resin foam film characterized by being K or less.   2. The polyolefin resin according to claim 1, wherein the mass ratio of the polyolefin resin (A) and the thermal expansion microcapsule (B) is (A) :( B) = 97-80: 3-20. Foam film.   The polyolefin resin foam film according to claim 1 or 2, wherein the tensile strength (MD) is 2.0 MPa or more.   The polyolefin-based resin foam film according to any one of claims 1 to 3, further comprising titanium oxide.   A laminated film comprising the polyolefin resin foam film according to any one of claims 1 to 4.   The laminated film according to claim 5, having the polyolefin resin foam film as an intermediate layer.   The laminated film according to claim 5 or 6, wherein the layer on the surface of the laminated film does not contain thermal expansion microcapsules.