JP6916615B2 - Ear strap for mask - Google Patents

Description

The present invention relates to a mask ear strap attached to a mask body.

Masks are used in various situations in the daily environment. Generally, a mask is composed of a mask body that covers the mouth and nose and a pair of strings provided on the left and right sides of the mask body to fix the mask body to the face. Is fixed to the face.

At this time, immediately after the user wears it, it is better to feel the tightening from the string body a little stronger, but if the mask is worn for a long time, there is a problem that the ear that comes into contact with the string body becomes painful. .. In particular, when working in a clean room, hospital, food warehouse, etc., the worker always wears a mask, and as a result of the string body holding the ear area for a long period of time, the pain in the ear area is increased.

In order to solve this problem, it has been proposed to use a flexible material for the string body (Patent Document 1) and to attach a cover to the string body (Patent Documents 2 and 3). On the other hand, Patent Document 4 discloses a sheet and a film of a 4-methyl-1-pentene / α-olefin copolymer having excellent stress relaxation properties as a material suitable for a string.

JP-A-2002-655878 Japanese Unexamined Patent Publication No. 2013-74927 Registered Utility Model No. 3205333 International Publication No. 2014/208564

In the material of the string body of Patent Documents 1 to 3 described above, by using a flexible polyurethane material or a rubber material, the force applied directly to the ear can be reduced, but the repulsive force due to the rubber elasticity becomes large, and the length becomes long. There is a problem that the ear hurts when worn for a long time.

On the other hand, the string body of Patent Document 4 can obtain high stress relaxation property but is difficult to expand and contract. Therefore, the above problem cannot be solved, and further improvement is required in order to achieve both elasticity and stress relaxation property. It has become.

An object of the present invention is to solve the above-mentioned problems of the prior art, to have high stress relaxation property and elasticity, and to gradually return after stretching to reduce the feeling of tightening over a long period of time. The purpose is to provide a mask ear strap that provides a fit.

The mask ear hook according to the present invention for achieving the above object is a mask ear hook having a multi-layered structure in which a core layer and a surface layer are connected to the mask body, and the core layer is 4-methyl. A polymer composition (Z) of a -1-pentene / α-olefin copolymer (A) and a thermoplastic elastomer (B), the surface layer of which is a thermoplastic elastomer (B), and the thermoplastic elastomer. (B) is a copolymer of one selected from the group consisting of polyethylene and polypropylene and one selected from the group consisting of polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, and α-olefin. Or selected from the group consisting of polyethylene and polypropylene, and selected from the group consisting of ethylene / propylene copolymers, ethylene / propylene / diene copolymers, ethylene / butene copolymers, and hydrogenated styrene butadiene. It is a mixture with one, and is characterized by having properties that satisfy the following requirements (1) and (2).
Requirement (1); The peak temperature of the loss tangent tan δ obtained by performing dynamic viscoelasticity measurement at a frequency of 10 rad / sec (1.6 Hz) in the temperature range of -40 to 150 ° C. is 15 to 40 ° C. thing.
Requirement (2); The tensile elongation at break measured at a tensile speed of 200 mm / min in accordance with JIS K7127 shall be 300 to 1000%.

According to the ear strap for a mask according to the present invention, when the body temperature is transmitted, the tightening force received is gradually relaxed, and a comfortable wearing feeling can be continuously obtained.

It is explanatory drawing of the mask. It is sectional drawing of the ear strap.

FIG. 1 is an explanatory view of a mask to which the ear strap of the present invention is attached, and FIG. 2 is a cross-sectional view of the ear strap.

The mask shown in FIG. 1 is composed of a mask main body 1 and an ear strap 2. Various materials and shapes of the mask main body 1 are selected according to bacteria, dust, harmful gas, etc. to be protected. On the other hand, it is desirable to use a material for the ear strap 2 for bringing the mask body 1 into close contact with the face so as not to put a load on the user's ear as much as possible even if the mask body 1 is used for a long time. That is, the ear strap 2 is required to have a material that increases the degree of adhesion to the face, moderately relieves stress over time, and maintains the required elongation.

FIG. 2 is a cross-sectional view of the ear strap 2 in the thickness direction. The ear strap 2 is composed of a laminated sheet of a core layer 2a which is a stress relaxation layer and a surface layer 2b which is an elastic structure and covers the core layer 2a from both sides, and cuts the sheet into strips. Obtained by The ear strap 2 has a predetermined width and thickness in consideration of the fit to the ear, and is dimensionally, for example, 0.1 to 5 mm in width and 0.05 to 1 mm in thickness.

In the examples, the ear strap 2 having a multi-layer structure of two types and three layers is illustrated, but the ear strap 2 has a core layer 2a in the center and a surface layer 2b on the outer circumference, for example, a diameter of 0.1 to 1. It may be formed into a circular cross section of 5 mm.

The material of the core layer 2a of the ear strap 2 is composed of a 4-methyl-pentene / α-olefin copolymer (A) (hereinafter referred to as “copolymer (A)”), and is thermoplastic as necessary. Elastomer (B) is added. A thermoplastic elastomer (B) is mainly used as the material of the surface layer 2b.

The composition and physical properties of the materials of the core layer 2a and the surface layer 2b will be described below.

[Core layer 2a]
The core layer 2a contains the copolymer (A), preferably composed of the copolymer (A) and the thermoplastic elastomer (B). The copolymer (A) constituting the elastic structure of the core layer 2a will be described below.

[Copolymer (A)]
It is desirable that the copolymer (A) satisfies the following requirements.

Requirement (4); The melting point (Tm) of the copolymer (A) measured by a differential scanning calorimeter (DSC) shall not be observed.

By satisfying this requirement (4), it is possible to improve the tensile physical characteristics of the surface layer 2b, which is an elastic structure, and to moderate the change with time of the tensile permanent strain.

Requirement (5); The copolymer (A) is a structural unit (i) derived from 4-methyl-1-pentene and a structural unit derived from α-olefin (excluding 4-methyl-1-pentene). The total of (ii) is 100 mol%, and the constituent unit (i) is 50 to 90 mol%, and the constituent unit (ii) is 10 to 50 mol%.

That is, the lower limit of the ratio of the constituent unit (i) is 50 mol%, preferably 60 mol%, and more preferably 68 mol%. On the other hand, the upper limit of the ratio of the constituent unit (i) is 90 mol%, preferably 87 mol%, more preferably 86 mol%, and particularly preferably 80 mol% or less. ..

As described above, in the embodiment, when the ratio of the structural unit (i) in the copolymer (A) is equal to or higher than the lower limit value, the peak value temperature of the loss tangent tan δ is held near room temperature, so that the shape can be followed. It has excellent properties and stress relaxation properties, and has appropriate flexibility when the ratio of the constituent unit (i) is equal to or lower than the upper limit value.

The upper limit of the ratio of the constituent unit (ii) is 85 mol%, but it is preferably 40 mol%, more preferably 35 mol%, and even more preferably 32 mol%. On the other hand, the lower limit of the ratio of the constituent unit (ii) is 13 mol%, more preferably 14 mol%, and particularly preferably 20 mol%.

Examples of the α-olefin that derives the structural unit (ii) include ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-undecene, 1-dodecene, 1-tetradecene, and the like. Linear α-olefins and 3-methyls having 2 to 20 carbon atoms, preferably 2 to 15 carbon atoms, more preferably 2 to 10 carbon atoms such as 1-hexadecene, 1-octadecene, and 1-eicosene. -1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene, 4,4-dimethyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene, 4 Examples thereof include branched α-olefins having 5 to 20 carbon atoms, preferably 5 to 15 carbon atoms, such as −ethyl-1-hexene and 3-ethyl-1-hexene. Among these, ethylene, propylene, 1-butene, 1-pentene, 1-hexene and 1-octene are preferable, and ethylene and propylene are particularly preferable.

Here, in the embodiment, the copolymer (A) usually consists of only the structural unit (i) and the structural unit (ii). However, if the copolymer (A) is in a small amount (for example, 10 mol% or less) that does not impair the object of the present invention, the copolymer (A) is a structural unit in addition to the structural unit (i) and the structural unit (ii). (Iii) may further include a structural unit derived from another monomer that is neither 4-methyl-1-pentene nor the α-olefin leading to the structural unit (ii). Preferred specific examples of such other monomers include 5-vinyl-2-norbornene and 5-ethylidene-when the copolymer (A) is a 4-methyl-1-pentene-propylene copolymer. 2-Norbornene and the like can be mentioned.

Requirement (6); The ultimate viscosity [η] measured at 135 ° C. in decalin is usually 0.1 to 5.0 dl / g, preferably 0.5 to 4.0 dl / g, 0.5 to 3 More preferably, it is in the range of .5 dl / g.

As will be described later, when hydrogen is used in combination during polymerization, the molecular weight can be controlled, and a low molecular weight substance to a high molecular weight substance can be freely obtained, and the ultimate viscosity [η] can be adjusted. If the ultimate viscosity [η] is smaller than 0.1 dl / g or larger than 5.0 dl / g, the moldability when processing the polymer composition into a sheet or the like may be impaired.

Requirement (7); The density (measured by ASTM D1505) is more ^{preferably 870-830 kg / m 3} , preferably 856-830 kg / m ³ , and 855-830 kg / m ³ .

The details of the measurement conditions and the like are as described in the column of Examples described later. The density can be appropriately changed depending on the comonomer composition ratio of the copolymer (A), and the copolymer (A) having a density within the above range is advantageous for producing a lightweight sheet.

Requirement (8); The peak temperature of the loss tangent tan δ of the copolymer (A) obtained by performing dynamic viscoelasticity measurement at a frequency of 10 rad / sec (1.6 Hz) in the temperature range of -40 to 150 ° C. The temperature is preferably 20 to 40 ° C, more preferably 25 to 40 ° C.

By setting the peak temperature of the loss tangent tan δ of the copolymer (A) to the above temperature range, the value of the loss tangent tan δ at room temperature can be further increased. In addition, by having a peak value of tangent tan δ at room temperature, the stress after tension can be relaxed according to the speed of tension and deformation, and the problem of high stress relaxation and uncomfortable wearing when mounted is solved. It is possible to change the vibration absorption, the hardness of the material, and the unevenness followability.

_{Requirement (3): Tensile permanent strain (PS 10M} ) obtained 10 minutes after stretching 150% at a tensile speed of 200 mm / min according to JIS K7127 is 10% to 45% in the range of 10% to 50%. Is preferable, and 10 to 30% is more preferable.

Since the copolymer (A) satisfying such properties is composed of only polyolefin, the load on the environment is reduced, and the stretched core layer 2a does not shrink immediately but shrinks over time. When attached to the face as an ear strap 2, the tightening due to elasticity is greatly reduced, and the problem of uncomfortable wearing is also solved.

Requirement (2): The tensile elongation at break when measured at a tensile speed of 200 mm / min in accordance with JIS K7127 shall be 300% to 1000%.

The ear strap 2 satisfying such characteristics can be stretched to an arbitrary length without breaking when the ear strap 2 is stretched when worn on the face.

[Method for producing copolymer (A)]
The method for producing the copolymer (A) is not particularly limited, but the copolymer (A) is an appropriate polymerization of, for example, 4-methyl-1-pentene and the above-mentioned "α-olefin leading to the structural unit (ii)". It can be obtained by polymerizing in the presence of a catalyst.

Here, as the polymerization catalyst that can be used in this example, conventionally known catalysts such as magnesium-supported titanium catalysts, International Publication No. 1/53369 Pamphlet, International Publication No. 1/27124, Japanese Patent Application Laid-Open No. 3-193996 or The metallocene catalysts described in JP-A-2-41303, International Publication No. 2011/55803, International Publication No. 2014/50817 and the like are preferably used.

[Thermoplastic Elastomer (B)]
Even if a thermoplastic elastomer (B) other than the copolymer (A) is added to the core layer 2a constituting the ear strap 2 as long as the excellent properties of the copolymer (A) are not impaired. good.

When the thermoplastic elastomer (B) is added to the copolymer (A), assuming that the total amount thereof is 100 parts by mass, the polymer (A) in the composition can be used from the viewpoint of flexibility and stress relaxation. The upper limit of the content is usually 80 parts by mass, more preferably 75 parts by mass, particularly preferably 70 parts by mass, and the lower limit is usually 50 parts by mass, preferably 60 parts by mass.

In other words, the lower limit of the content of the thermoplastic elastomer (B) is usually 20 parts by mass, more preferably 25 parts by mass, particularly preferably 30 parts by mass, and the upper limit is preferably 50 parts by mass. 40 parts by mass is particularly preferable.

The thermoplastic elastomer (B) referred to in this example is a polymer that exhibits a thermoplastic property when heated to a temperature equal to or higher than the melting point, and a rubber elastic property at room temperature. The embodiment of the polyolefin-based elastomer as a specific example of the thermoplastic elastomer (B) is one selected from the group consisting of polyethylene and polypropylene, polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisobutylene, polyisobutylene, and α-. It is a copolymer with one selected from the group consisting of olefins.

The form of copolymerization may be either block copolymerization or graft copolymerization, but the form of copolymerization is random copolymerization only in the case of one selected from the group consisting of polyethylene and polypropylene and a copolymer composed of α-olefin. There may be. The α-olefin is an olefin having a double bond at one end of the molecular chain, and 1-butene, 1-octene and the like are preferably used.

For example, a block copolymer of a polyolefin block that forms a highly crystalline polymer such as polypropylene that serves as a hard portion and a monomer copolymer that exhibits amorphousness that serves as a soft portion can be mentioned. Specifically, olefin (crystalline) / ethylene / butylene / olefin block copolymers, polypropylene / polyolefin (amorphous) / polypropylene block copolymers and the like can be exemplified.

Specific examples include the trade name DYNARON (registered trademark) from JSR Co., Ltd., the trade name Toughmer (registered trademark), Notio (registered trademark) from Mitsui Kagaku Co., Ltd., and the trade name ENGAGE from Dow Chemical Co., Ltd. ^TM , VERSIFY ^{TM , and those commercially available under the trade name Vistamaxx TM} from Exxon Mobile Chemical Co., Ltd. can be mentioned.

The second aspect of the polyolefin-based elastomer referred to in this example is one selected from the group consisting of polyethylene and polypropylene, an ethylene / propylene copolymer, an ethylene / propylene / diene copolymer, and an ethylene / butene copolymer. It is a mixture with one selected from the group consisting of hydrogenated styrene-butadiene. At this time, the ethylene / propylene copolymer, the ethylene / propylene / diene copolymer, and the ethylene / butene copolymer may be partially or completely crosslinked.

Specific examples include the trade name Mirastomer (registered trademark) from Mitsui Chemicals, Inc., the trade name Esporex (registered trademark) from Sumitomo Chemical Corporation, the trade name Thermolan (registered trademark) from Mitsubishi Chemical Corporation, and Zelas (registered trademark). Registered trademark), trade name Santoprene (registered trademark) from Exxon Mobile Chemicals, etc.

[Surface layer 2b]
The surface layer 2b according to the stretchable structure having a multi-layer structure of this embodiment is made of a thermoplastic elastomer (B). As such a thermoplastic elastomer (B), the above-mentioned thermoplastic elastomer (B) can be used as it is without limitation.

Further, the surface layer 2b in this embodiment is a layer in which at least a part of the surface layer 2b is in contact with the core layer 2a. Here, "at least a part of the surface layer is in contact with the core layer 2a" means that the surface layer 2b is in contact with a part of the core layer 2a, or the surface layer 2b is in contact with the entire core layer 2a. This means that the contact ratio between the core layer 2a and the surface layer 2b is preferably 30% to 100%, more preferably 50% to 100%, based on the total area of the core layer 2a. ..

The ratio of the thickness (thickness of the core layer 2a / thickness of the surface layer 2b) in the laminate of this example is not particularly limited, but is preferably 1 to 100/100/1 to 100, preferably 1 to 50. / 100/1 to 50 is more preferable.

[Manufacturing method of ear strap 2]
The manufacturing method of the ear strap 2 of this embodiment is not particularly limited, and a conventionally known manufacturing method can be applied. For example, it can be obtained by molding with a general extrusion molding machine in which a mouthpiece is installed in the shape of the ear strap 2, cutting a sheet-shaped product into the shape of the ear strap 2, or slit cutting. Be done. For example, a sheet may be formed by molding with a uniaxial extruder at a cylinder temperature of 170 to 250 ° C. and a cast roll temperature of 0 to 70 ° C.

The thickness of the sheet depends on the intended use, but when it is usually 5 to 1000 μm, preferably 30 to 200 μm, the productivity of the sheet is excellent, pinholes do not occur during the molding of the sheet, and sufficient strength is obtained. It is also preferable because it can also be obtained.

Further, the surface of the sheet may be embossed, or may be stretched at the time of sheet molding or after molding. Further, the sheet obtained by molding may be annealed at a temperature lower than the melting point of the resin.

The sheet may be produced by an inflation molding method. Specifically, an inflation film can be obtained by extruding from an inflation die in an upward direction opposite to the direction of gravity at a predetermined cylinder temperature by a uniaxial extruder.

The pick-up speed of the inflation film is usually 2 to 40 m / min, preferably 4 to 30 m / min. The thickness of the film is not particularly limited, but is usually 10 to 300 μm, preferably 20 to 250 μm.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is changed.
Various physical properties according to Examples and Comparative Examples were measured by the following methods.

[composition]
The content (mol%) of each structural unit (4-methyl-1-pentene and α-olefin) in the 4-methyl-1-pentene copolymer (A) ^{was measured by 13} C-NMR.

Measuring device: Nuclear magnetic resonance device (ECP500 type, manufactured by JEOL Ltd.)
Observation nucleus: ¹³ C (125 MHz)
Sequence: Single pulse Proton decoupling Pulse width: 4.7 μsec (45 ° pulse)
Repeat time: 5.5 seconds Number of integrations: 10,000 times or more Solvent: Mixed solvent of orthodichlorobenzene / deuterated benzene (volume ratio: 80/20) Sample concentration: 55 mg / 0.6 ml
Measurement temperature: 120 ° C
Reference value of chemical shift: 27.50ppm

[Ultimate viscosity]
The ultimate viscosity [η] of the copolymer (A) was measured at 135 ° C. in a decalin solvent using an Ubbelohde viscous meter as a measuring device. After dissolving about 20 mg of the specified 4MP1 copolymer in 25 ml of decalin, the specific viscosity η _sp is measured in an oil bath at 135 ° C. using an Ubbelohde viscometer. After adding 5 ml of decalin to this decalin solution and diluting it, the specific viscosity η _sp is measured in the same manner as above. _{This dilution operation was repeated twice more, and the value of η sp} / C when the concentration (C) was extrapolated to 0 was defined as the ultimate viscosity [η] (unit: dl / g) by the following formula (1). Ask.
[Η] = lim (η _sp / C) (C → 0) ・ ・ ・ (1)

[density]
The density of the copolymer (A) was measured according to JIS K7112 (density gradient tube method). This density (kg / m ³ ) was used as an index of lightness.

[Melting point (Tm)]
The melting point (Tm) of the copolymer (A) was measured using a differential scanning calorimeter (DSC220C type, manufactured by Seiko Instruments Inc.) as a measuring device. Approximately 5 mg of the copolymer (A) is sealed in a measuring aluminum pan and heated from room temperature to 200 ° C. at 10 ° C./min. To completely melt the copolymer (A), it is held at 200 ° C. for 5 minutes and then cooled to −50 ° C. at 10 ° C./min. After leaving it at −50 ° C. for 5 minutes, it is heated to 200 ° C. at 10 ° C./min for the second time, and the peak temperature (° C.) at this second heating is defined as the melting point (Tm) of the copolymer (A). And. When a plurality of peaks are detected, the peak detected on the highest temperature side is adopted.

[Measurement of dynamic viscoelasticity]
A press sheet having a thickness of 3 mm was used as a measurement sample, and a strip piece of 45 mm × 10 mm × 3 mm necessary for dynamic viscoelasticity measurement was cut out. Using MCR301 manufactured by Anton Pearl Co., Ltd., the temperature dependence of dynamic viscoelasticity from -40 to 150 ° C. was measured at a frequency of 10 rad / sec, and the loss tangent due to the glass transition temperature was measured in the range of 0 to 40 ° C. The temperature at which tan δ reaches the peak value (maximum value) (hereinafter, also referred to as “peak value temperature”) and the value of the loss tangent tan δ at that time were measured.

[Mechanical properties (tensile breaking elongation, tensile breaking strength, Young's modulus)]
A sheet having a thickness of 400 μm cut into a dumbbell shape having a width of 25 mm and a length of 100 mm was used as a test piece. In accordance with JIS K7127 (1999), using a tensile tester (universal tensile tester 3380, manufactured by Instron), the test piece is subjected to the conditions of a chuck distance of 50 mm, a tensile speed of 200 mm / min, and a temperature of 23 ° C. Tensile modulus (YM) (unit: MPa), tensile elongation at break (EL) (unit:%), and tensile strength at break (TS) (unit: MPa) were measured.

[Tension permanent strain]
A sheet having a thickness of 400 μm cut into a JIS K7127 No. 5 dumbbell shape was used as a test piece. In accordance with JIS K7127 (1999), a tensile tester (universal tensile tester 3380, manufactured by Instron) is used to make 150% of the sheet under the conditions of a distance between chucks of 80 mm, a tensile speed of 200 mm / min, and a temperature of 23 ° C. It was stretched and held for 10 minutes. The held chuck was released, the sheet was removed from the tensile tester, the distance between the chucks 1 minute and 10 minutes after release was measured, and the tensile permanent strain was calculated from the following equation (2).
PS = (I-I ₀ ) / I ₀ x 100 ... (2)
PS: Tensile permanent strain (%)
I: Distance between chucks after 1 minute or 10 minutes (mm)
I ₀ : Distance between chucks before the test (mm)
In addition, the tensile permanent strain (PS _10M ) obtained 10 minutes after opening was determined.

<Synthesis example 1>
[Synthesis of 4-methyl-1-pentene / α-olefin copolymer (A1)]
300 ml of n-hexane (dried on activated alumina in a dry nitrogen atmosphere) and 450 ml of 4-methyl-1-pentene were placed in a SUS autoclave with a volume of 1.5 liters sufficiently nitrogen-substituted. It was charged at 23 ° C. 0.75 ml of a 1.0 mM / ml toluene solution of triisobutylaluminum (TIBAL) was charged into this autoclave, and the stirrer was rotated. Next, the autoclave was heated to an internal temperature of 60 ° C. and pressurized with propylene so that the total pressure (gauge pressure) was 0.40 MPa.

Subsequently, 1 mM methylaluminoxane and 0.01 mM diphenylmethylene (1-ethyl-3-t-butyl-cyclopentadienyl) (2,7-di-t) prepared in advance in terms of Al. 0.34 ml of a toluene solution containing -butyl-fluorenyl) zirconium dichloride was press-fitted into an autoclave with nitrogen to initiate a polymerization reaction. During the polymerization reaction, the temperature was adjusted so that the internal temperature of the autoclave was 60 ° C.

60 minutes after the start of polymerization, 5 ml of methanol was press-fitted into the autoclave with nitrogen to stop the polymerization reaction, and the inside of the autoclave was depressurized to atmospheric pressure. After depressurization, acetone was added to the reaction solution with stirring to obtain a polymerization reaction product containing a solvent.

Then, the obtained polymerization reaction product containing the solvent was dried under reduced pressure at 100 ° C. for 12 hours to obtain 36.9 g of a powdery copolymer (A1).

The content of 4-methyl-1-pentene in the copolymer (A1) was 72.5 mol%, and the content of propylene was 27.5 mol%. The density of the copolymer (A1) was 839 kg / m ³ . The limit viscosity [η] of the copolymer (A1) is 1.5 dl / g, the weight average molecular weight (Mw) is 337,000, the molecular weight distribution (Mw / Mn) is 2.1, and the melt flow. The rate (MFR) was 11 g / 10 min. The melting point (Tm) of the copolymer (A1) was not observed. The peak temperature of the loss tangent tan δ measured by viscoelasticity measurement was 30 ° C., and the peak value was 2.7.

Examples of the present invention will be described below. Table 1 summarizes the composition of each material of the core layer 2a and the surface layer 2b, the physical properties of the core layer 2a, the physical properties of the sheet composed of the core layer 2a and the surface layer 2b, and the wearing feeling by the sensory test. rice field.

Other resins used were as follows. Olefin-based thermoplastic elastomer (B1) (manufactured by Mitsui Chemicals, Inc., trade name Mirastomer (registered trademark) 5030NS):
Olefin-based thermoplastic elastomer (B2) (manufactured by Mitsui Kagaku Co., Ltd., trade name Toughmer (registered trademark) PN-2060): Olefin-based thermoplastic elastomer (B3) (manufactured by Mitsui Kagaku Co., Ltd., trade name Mirastomer (registered trademark)) ) 9070NS): The physical characteristics of these resin materials are shown in Table 2 together with the copolymer (A1).

<Example 1>
A core layer 2a consisting of 70 parts by mass of the copolymer (A1) and 30 parts by mass of an olefin-based thermoplastic elastomer (B1) (manufactured by Mitsui Chemicals, Inc., trade name Mirastomer (registered trademark) 5030NS), and an olefin-based thermoplastic elastomer. (B1) (Product name: Mirastromer (registered trademark) 5030NS manufactured by Mitsui Kagaku Co., Ltd.) A 20 mmφ single-screw extruder (single) equipped with a T-die with a lip width of 200 mm and a multilayer sheet with a surface layer 2b consisting of 100 parts by mass. The sheet of Example 1 was obtained by molding by coextrusion using a shaft two-kind three-layer sheet molding machine (manufactured by Technobel Co., Ltd.). The layer structure of the sheet is two types and three layers composed of a surface layer 2b (100 μm) / a core layer 2a (200 μm) / a surface layer 2b (100 μm). Table 1 shows the results of physical property evaluation of the obtained sheet.

<Example 2>
A core layer 2a consisting of 70 parts by mass of the copolymer (A1) and 30 parts by mass of an olefin-based thermoplastic elastomer (B1) (manufactured by Mitsui Chemicals, Inc., trade name Mirastomer (registered trademark) 5030NS), and an olefin-based thermoplastic elastomer. (B2) (Product name Toughmer (registered trademark) PN-2060 manufactured by Mitsui Chemicals Co., Ltd.) A 20 mmφ single-screw extruder equipped with a T-die with a lip width of 200 mm on a multilayer sheet with a surface layer 2b consisting of 100 parts by mass. The sheet of Example 2 was obtained by molding by coextrusion using (single-screw two-kind three-layer sheet molding machine, manufactured by Technobel Co., Ltd.). The layer structure of the sheet is two types and three layers composed of a surface layer 2b (80 μm) / a core layer 2a (240 μm) / a surface layer 2b (80 μm). Table 1 shows the results of physical property evaluation of the obtained sheet.

<Example 3>
A core layer 2a consisting of 50 parts by mass of the copolymer (A1) and 50 parts by mass of an olefin-based thermoplastic elastomer (B1) (manufactured by Mitsui Chemicals, Inc., trade name Mirastomer (registered trademark) 5030NS), and an olefin-based thermoplastic elastomer. (B3) (Product name Mirastromer (registered trademark) 9070NS manufactured by Mitsui Chemicals Co., Ltd.) A 20 mmφ single-screw extruder (single) equipped with a T-die with a lip width of 200 mm and a multilayer sheet with a surface layer 2b consisting of 100 parts by mass. The sheet of Example 3 was obtained by molding by coextrusion using a shaft two-kind three-layer sheet molding machine (manufactured by Technobel Co., Ltd.). The layer structure of the sheet is two types and three layers composed of a surface layer 2b (40 μm) / a core layer 320 μm) / a surface layer 2b (40 μm). Table 1 shows the results of physical property evaluation of the obtained sheet.

<Example 4>
A core layer 2a consisting of 70 parts by mass of the copolymer (A1) and 30 parts by mass of an olefin-based thermoplastic elastomer (B1) (manufactured by Mitsui Chemicals, Inc., trade name Mirastomer (registered trademark) 3030NS), and an olefin-based thermoplastic elastomer. (B1) (Product name Mirastomer (registered trademark) 5030NS manufactured by Mitsui Chemicals Co., Ltd.) 30 parts by mass and 70 parts by mass of olefin-based thermoplastic elastomer (B3) (Product name Mirastomer (registered trademark) 9070NS manufactured by Mitsui Chemicals Co., Ltd.) A multi-layer sheet with a surface layer 2b consisting of parts is co-extruded using a 20 mmφ single-screw extruder (single-screw two-kind three-layer sheet molding machine, manufactured by Technobel Co., Ltd.) equipped with a T-die having a lip width of 200 mm. The sheet of Example 4 was obtained. The layer structure of the sheet is two types and three layers composed of a surface layer 2b (100 μm) / a core layer 2a (200 μm) / a surface layer 2b (100 μm). Table 1 shows the results of physical property evaluation of the obtained sheet.

<Example 5>
A core layer 2a consisting of 70 parts by mass of the copolymer (A1) and 30 parts by mass of an olefin-based thermoplastic elastomer (B2) (manufactured by Mitsui Chemicals, Inc., trade name Mirastomer (registered trademark) 5030NS), and an olefin-based thermoplastic elastomer. (B3) (Product name Toughmer (registered trademark) PN-2060 manufactured by Mitsui Chemicals Co., Ltd.) A 20 mmφ single-screw extruder equipped with a T-die with a lip width of 200 mm on a multilayer sheet with a surface layer 2b consisting of 100 parts by mass. The sheet of Example 5 was obtained by molding by coextrusion using (single-screw two-kind three-layer sheet molding machine, manufactured by Technobel Co., Ltd.). The layer structure of the sheet is two types and three layers composed of a surface layer 2b (100 μm) / a core layer 2a (200 μm) / a surface layer 2b (100 μm). Table 1 shows the results of physical property evaluation of the obtained sheet.

<Comparative example 1>
A 200 mmφ single-screw extruder (single-screw two-kind three-layer) equipped with a T-die with a lip width of 200 mm on a single-layer sheet consisting of only 100 parts by mass of 4-methyl-1-pentene / α-olefin copolymer (A1). Using a sheet molding machine (manufactured by Technobel Co., Ltd.), molding was performed by coextrusion to obtain a sheet of Comparative Example 1. Table 1 shows the results of physical property evaluation of the obtained sheet.

<Comparative example 2>
Olefin-based thermoplastic elastomer (B1) (manufactured by Mitsui Chemicals, Inc., trade name Mirastomer (registered trademark) 5030NS) A single-layer sheet consisting of only 100 parts by mass, and a 20 mmφ single-screw extrusion equipped with a T-die with a lip width of 200 mm. Using a machine (single-screw two-kind three-layer sheet molding machine, manufactured by Technobel Co., Ltd.), molding was performed by coextrusion to obtain a sheet of Comparative Example 2. Table 1 shows the results of physical property evaluation of the obtained sheet.

<Comparative example 3>
Using a commercially available rubber cord mask, the elastic cord portion was cut and the physical properties were evaluated. The evaluation results are shown in Table 1.

As described above, as is clear from Table 1, all of Examples 1 to 5 are superior to Comparative Examples 1 to 3 in the low temperature characteristics and the wearing feeling by the sensory test.

1 Mask body 2 Ear strap 2a Core layer 2b Surface layer

Claims (4)

In the mask ear strap, which is connected to the mask body and has a multi-layer structure consisting of a core layer and a surface layer.
The core layer is a polymer composition (Z) of a 4-methyl-1-pentene / α-olefin copolymer (A) and a thermoplastic elastomer (B), and the surface layer is a thermoplastic elastomer (B). And
The thermoplastic elastomer (B) is selected from the group consisting of polyethylene and polypropylene, and one selected from the group consisting of polybutadiene, hydrogenated polybutadiene, polyisoprene, hydrogenated polyisoprene, polyisobutylene, and α-olefin. Consists of ethylene-propylene copolymer, ethylene-propylene-diene copolymer, ethylene-butene copolymer, hydrogenated styrene-butadiene, and one selected from the group consisting of polyethylene and polypropylene. It is a mixture with one selected from the group,
An ear strap for a mask characterized by having characteristics that satisfy the following requirements (1) and (2).
Requirement (1); The peak temperature of the loss tangent tan δ obtained by performing dynamic viscoelasticity measurement at a frequency of 10 rad / sec (1.6 Hz) in the temperature range of -40 to 150 ° C. is 15 to 40 ° C. thing.
Requirement (2); The tensile elongation at break measured at a tensile speed of 200 mm / min in accordance with JIS K7127 shall be 300 to 1000%. The mask ear strap according to claim 1, wherein the copolymer (A) has a property of satisfying the following requirement (3).
_{Requirement (3); The tensile permanent strain (PS 10M} ) obtained 10 minutes after stretching by 150% at a tensile speed of 200 mm / min according to JIS K7127 is in the range of 1 to 50%. The core layer following requirement (4) mask earhook cord according to claim 2, wherein the score satisfy to (8).
Requirement (4); The copolymer (A) does not have a melting point (Tm) as measured by a differential scanning calorimeter (DSC).
Requirement (5); The copolymer (A) is derived from the structural unit (i) derived from 4-methyl-1-pentene and α-olefin (excluding 4-methyl-1-pentene). The total of the constituent unit (ii) is 100 mol%, the constituent unit (i) is 60 to 80 mol%, and the constituent unit (ii) is 20 to 40 mol%.
Requirement (6); The copolymer (A) has an ultimate viscosity [η] measured at 135 ° C. in decalin, which is usually 0.5 to 5.0 dl / g.
Requirement (7); The copolymer (A) has a density (measured by ASTM D1505) of 870 to 830 kg / m3.
Requirement (8); The copolymer (A) has a peak of tangent tan δ obtained by performing dynamic viscoelasticity measurement at a frequency of 10 rad / sec (1.6 Hz) in a temperature range of -40 to 150 ° C. The temperature should be 0-40 ° C or less. A mask comprising the mask ear strap according to any one of claims 1 to 3.

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