JP2011063773A - Polyurethane resin composition and polyurethane molded product for pressure-sensitive sensor, pressure-sensitive sensor and touch panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polyurethane resin composition for a pressure-sensitive sensor, which has excellent moisture resistance, water resistance, electric noise resistance and electromagnetic wave resistance, enabling the thickness of the sensor to be reduced, weight and production cost thereof to be reduced; and to provide a polyurethane molded product for the sensor, the sensor and a touch panel. <P>SOLUTION: The touch panel 1 includes the sensor 2 comprising the polyurethane molded product 4 for the sensor having photoelasticity and obtained by molding the polyurethane composition containing a polyisocyanate and an active hydrogen group-having compound having an active hydrogen group value of 30-550 mgKOH/g. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a polyurethane resin composition for a pressure sensor, a polyurethane molded body for a pressure sensor, a pressure sensor and a touch panel, and more specifically, a touch panel suitably used as an input device, and a polyurethane resin for a pressure sensor used therefor The present invention relates to a composition, a polyurethane molded body for a pressure sensor, and a pressure sensor.

Conventionally, a touch panel is widely known as an input device using a pressure-sensitive sensor.
As such a touch panel system, various systems such as a resistive film type, a capacitance system, an optical system, and an ultrasonic system have been proposed (for example, see Non-Patent Document 1).

“Fujikura Technical Review” No. 102, April 2002, p. 42-46

  However, resistance film type and capacitive type touch panels have low moisture resistance and water resistance, and thus may cause false detection when touched with a wet or wet finger. In addition, resistance film type and capacitive type touch panels have low electric noise resistance and electromagnetic wave resistance, and therefore, when used in an environment that generates electric noise and electromagnetic waves such as in a factory or around a motor, false detection occurs. There is a case.

In addition, the optical touch panel needs to optically read a finger, and thus requires a space for allowing detection light to pass therethrough.
Furthermore, an ultrasonic touch panel requires an ultrasonic generator, which increases the weight and costs.
An object of the present invention is a polyurethane resin composition for pressure-sensitive sensors, which is excellent in moisture resistance, water resistance, electrical noise resistance and electromagnetic wave resistance, can be reduced in thickness and weight, and can reduce costs. An object of the present invention is to provide a polyurethane molded body for a pressure sensor, a pressure sensor, and a touch panel.

In order to achieve the above object, the polyurethane resin composition for a pressure sensitive sensor of the present invention is a polyurethane resin composition used for a pressure sensitive sensor, and has a polyisocyanate and an average active hydrogen group value of 30 to 550 mgKOH / g. And an active hydrogen group-containing compound.
Moreover, in the polyurethane resin composition for pressure sensitive sensors of this invention, it is suitable that an aromatic ring density | concentration is 15 to 25 weight%.

Moreover, the polyurethane molded body for pressure sensors of the present invention is obtained by molding the above-described polyurethane resin composition for pressure sensors, and is characterized by having photoelasticity.
Moreover, in the polyurethane molding for pressure-sensitive sensors of this invention, it is suitable that the maximum value of the photoelastic constant in -20-60 degreeC is 1000 * 10 < ^-12 > Pa < ^-1 > or more.
Moreover, in the polyurethane molding for pressure sensors of this invention, it is suitable that a glass transition temperature is -10-35 degreeC.

Moreover, the pressure sensor of this invention is provided with the above-mentioned polyurethane molded object for pressure sensors.
Moreover, the touch panel of this invention is equipped with the above-mentioned pressure-sensitive sensor, It is characterized by the above-mentioned.

The polyurethane molded product for pressure-sensitive sensors of the present invention obtained from the polyurethane resin composition for pressure-sensitive sensors of the present invention is excellent in photoelasticity, and further in excellent moisture resistance and water resistance while being lightened and reduced in weight. It has electric noise resistance and electromagnetic wave resistance.
Therefore, in the pressure-sensitive sensor of the present invention including the pressure-sensitive sensor polyurethane molded body, the stress generation location in the pressure-sensitive sensor polyurethane molded body is reliably identified by sensing stress strain while reducing the weight and weight. be able to.

  As a result, the touch panel of the present invention including the pressure sensor of the present invention can achieve reliable sensing while reducing the weight and weight of the device.

FIG. 1 shows a plan view of an embodiment of the touch panel according to the present invention (a mode in which a light emitting portion and a light receiving portion are arranged outside a polyurethane molded body for a pressure sensitive sensor). FIG. 2 shows a cross-sectional view of another embodiment of the touch panel according to the present invention (a mode in which the light emitting part and the light receiving part are arranged inside the polyurethane molded body for the pressure sensor).

The polyurethane resin composition for pressure-sensitive sensors of the present invention (hereinafter simply referred to as polyurethane resin composition) contains polyisocyanate and an active hydrogen group-containing compound.
Examples of the polyisocyanate include aromatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate, and aliphatic polyisocyanate.

  Aromatic polyisocyanates include, for example, 4,4'-, 2,4'- or 2,2'-diphenylmethane diisocyanate or mixtures thereof (MDI), 2,4- or 2,6-tolylene diisocyanate or mixtures thereof (TDI), 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, 1,5-naphthalene diisocyanate (NDI), m- or p-phenylene diisocyanate or mixtures thereof, 4,4'-diphenyl diisocyanate, 4, Aromatic diisocyanates such as 4'-diphenyl ether diisocyanate can be mentioned.

Examples of the araliphatic polyisocyanate include araliphatic diisocyanates such as 1,3-xylylene diisocyanate (XDI) or a mixture thereof, and tetramethylxylylene diisocyanate (TMXDI).
Examples of the alicyclic polyisocyanate include 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate, IPDI), 4,4'-, 2,4'- or 2,2'-dicyclohexyl. Methane diisocyanate or its mixture (H ₁₂ MDI), 1,3-bis (isocyanatomethyl) cyclohexane or its mixture (hydrogenated xylylene diisocyanate, H ₆ XDI), 2,5- or 2,6-bis (isocyanato) Methyl) norbornane or a mixture thereof (NBDI), 1,3-cyclopentane diisocyanate, 1,4- or 1,3-cyclohexane diisocyanate or a mixture thereof, methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexa And alicyclic diisocyanates such as diisocyanates.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate (TMDI), hexamethylene diisocyanate (HDI), 1,2-, 2,3- or 1,3-butylene diisocyanate, 2,4,4- Or aliphatic diisocyanate, such as 2,2,4-trimethylhexamethylene diisocyanate, is mentioned.

These polyisocyanates can be used alone or in combination of two or more.
Among these polyisocyanates, preferably, aromatic polyisocyanate, araliphatic polyisocyanate, alicyclic polyisocyanate, and more preferably, from the viewpoint of setting the aromatic ring concentration in the polyurethane resin composition within a predetermined range, Aromatic polyisocyanates and araliphatic polyisocyanates can be mentioned.

The active hydrogen group-containing compound is an organic compound having an active hydrogen group, and the active hydrogen group is an active hydrogen group that reacts with an isocyanate group of polyisocyanate, and examples thereof include a hydroxyl group, an amino group, and a thiol group. . Preferably, a hydroxyl group is used.
The active hydrogen group-containing compound has an average active hydrogen group value (when the active hydrogen group is a hydroxyl group, a hydroxyl value) of 30 to 550 mgKOH / g, preferably 35 to 350 mgKOH / g, more preferably It is 40-250 mgKOH / g, Especially preferably, it is 140-230 mgKOH / g.

When the active hydrogen group-containing compound is used alone, the average active hydrogen group value is the same as the active hydrogen group value of the active hydrogen group-containing compound.
The active hydrogen group value of each active hydrogen group-containing compound is calculated as a value (mgKOH / g) obtained by multiplying the number of moles of active hydrogen groups per unit weight (g) by 56100 (mgKOH).
In addition, when a plurality of active hydrogen group-containing compounds are used in combination, the average active hydrogen group value is obtained by multiplying the active hydrogen group value of each active hydrogen group-containing compound by the number of blended parts of the active hydrogen group-containing compound. Is added and divided by the total amount of blended parts of the active hydrogen group-containing compound.

Specifically, the average active hydrogen group value of the active hydrogen group-containing compound in which two types of active hydrogen group-containing compounds AH1 and AH2 are used is represented by the following formula.
Average active hydrogen group value = [(AH1 × M) + (AH2 × N)] / (M + N)
AH1: Active hydrogen group value of active hydrogen group-containing compound AH1 M: Number of blended parts of active hydrogen group-containing compound AH1 AH2: Active hydrogen group number of active hydrogen group-containing compound AH2 N: Number of blended parts of active hydrogen group-containing compound AH2 Average activity If the hydrogen group value exceeds the above-mentioned range, the desired photoelasticity cannot be obtained in the polyurethane molded product for pressure-sensitive sensors. On the other hand, if the average active hydrogen group value is less than the above-mentioned range, the glass transition temperature Becomes excessively low, and the workability decreases.

Examples of the active hydrogen group-containing compound include polyols, polyamines, polythiols and the like. Preferably, a polyol is used.
Examples of the polyol include a low molecular weight polyol and a macropolyol.
The low molecular weight polyol is a compound having two or more hydroxyl groups and a number average molecular weight of 40 or more and less than 350, such as ethylene glycol, propylene glycol, 1,4-butylene glycol, 1,3-butylene glycol, 1,2- Butylene glycol, 2-methyl-1,3-propanediol, 1,5-pentanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 2,4-diethyl-1,5-pentanediol, 1 , 6-hexanediol, 2,6-dimethyl-1-octene-3,8-diol, alkane (carbon number 7 to 22) diol, cyclohexanedimethanol, hydrogenated bisphenol A, 1,4-dihydroxy-2-butene , Bishydroxyethoxybenzene, xylene glycol, bishydroxyethylene Dihydric alcohols such as terephthalate, bisphenol A, diethylene glycol, trioxyethylene glycol, tetraoxyethylene glycol, dipropylene glycol, trioxypropylene glycol, tetraoxypropylene glycol, such as glycerin, 2-methyl-2-hydroxymethyl-1 , 3-propanediol, 2,4-dihydroxy-3-hydroxymethylpentane, 1,2,6-hexanetriol, trimethylolpropane, 2,2-bis (hydroxymethyl) -3-butanol and other aliphatic triols (C8-C24) trihydric alcohol, for example, tetramethylolmethane (pentaerythritol), tetravalent alcohol such as diglycerin, for example, pentavalent alcohol such as xylitol For example, sorbitol, mannitol, allitol, iditol, dulcitol, altritol, inositol, hexahydric alcohols such as dipentaerythritol, for example, 7-valent alcohols such as perseitol, for example, 8 monohydric alcohol and sucrose.

These low molecular weight polyols can be used alone or in combination of two or more.
The macropolyol is a compound having two or more hydroxyl groups and a number average molecular weight of 350 or more. For example, polyether polyol, polyester polyol, polycarbonate polyol, polyurethane polyol, polyoxyalkylene polyester block copolymer polyol, acrylic polyol, epoxy Examples include polyols, natural oil polyols, silicone polyols, fluorine polyols, and polyolefin polyols.

Examples of the polyether polyol include polyoxyalkylene polyols such as polypropylene polyol and polytetramethylene ether polyol.
Examples of the polypropylene polyol include addition polymers of alkylene oxides such as ethylene oxide and propylene oxide (including random and / or block copolymers of two or more alkylene oxides) using the above-described low molecular weight polyol as an initiator. Is mentioned.

Examples of the polytetramethylene ether polyol include a ring-opening polymer obtained by cationic polymerization of tetrahydrofuran, and amorphous polytetramethylene ether glycol obtained by copolymerizing the above-described dihydric alcohol with a polymerization unit of tetrahydrofuran.
Examples of the polyester polyol include polyester polyols obtained by reacting the above-described low molecular weight polyols with polybasic acids or acid anhydrides or acid halides thereof.

  Examples of the polybasic acid and its acid anhydride or its acid halide include oxalic acid, malonic acid, succinic acid, methyl succinic acid, glutaric acid, adipic acid, 1,1-dimethyl-1,3-dicarboxypropane, 3 -Methyl-3-ethylglutaric acid, azelaic acid, sebacic acid, other aliphatic dicarboxylic acids (C11 to C13), hydrogenated dimer acid, maleic acid, fumaric acid, itaconic acid, orthophthalic acid, isophthalic acid, terephthalic acid , Carboxylic acids such as toluene dicarboxylic acid, dimer acid and het acid, and acid anhydrides derived from these carboxylic acids such as oxalic anhydride, succinic anhydride, maleic anhydride, phthalic anhydride, anhydrous 2 -Alkyl (C12-C18) succinic acid, tetrahydrophthalic anhydride, trimellitic anhydride, Acid halide derived from such those of carboxylic acids, such as oxalic acid dichloride, adipic acid dichloride, and the like sebacic acid dichloride.

Examples of polyester polyols include polycaprolactone polyols and polyvalerolactone polyols obtained by ring-opening polymerization of lactones such as ε-caprolactone and γ-valerolactone, for example, using the above-described low molecular weight polyol as an initiator. And lactone polyester polyols.
Further, as the polyester polyol, for example, the above-described low molecular weight polyol and hydroxycarboxylic acid such as a hydroxyl group-containing vegetable oil fatty acid (for example, castor oil fatty acid containing ricinoleic acid, hydrogenated castor oil fatty acid containing 12-hydroxystearic acid) and the like And vegetable oil-based polyester polyols obtained by a condensation reaction under known conditions.

The polycarbonate polyol can be obtained, for example, by reacting phosgene, dialkyl carbonate, diallyl carbonate, alkylene carbonate or the like in the presence or absence of a catalyst using the above-described low molecular weight polyol as an initiator.
As the polyurethane polyol, the polyester polyol, polyether polyol and / or polycarbonate polyol obtained as described above are reacted with the above-described polyisocyanate at a ratio in which the equivalent ratio of hydroxyl group to isocyanate group (OH / NCO) exceeds 1. Thus, it can be obtained as a polyester polyurethane polyol, a polyether polyurethane polyol, a polycarbonate polyurethane polyol, or a polyester polyether polyurethane polyol.

  As the polyoxyalkylene polyester block copolymer polyol, for example, as described in Japanese Patent Publication No. 48-10078, a polyoxyalkylene polyol having a structure in which a polyester chain is blocked, that is, a polyoxyalkylene polyol or The moiety substituted for the hydrogen atom of each hydroxy group of the derivative having a hydroxyl group is represented by the general formula (1)

(Wherein R1 and R2 are each a divalent hydrocarbon group, and n is an average greater than 1).
In the general formula (1), the divalent hydrocarbon group represented by R1 is, for example, a saturated aliphatic or aromatic polycarboxylic acid residue, and the divalent hydrocarbon group represented by R2 is, for example, cyclic Examples thereof include a residue obtained by cleaving a compound having an ether group, and n is preferably a number of 1 to 20.

This polyoxyalkylene polyester block copolymer polyol is obtained by reacting the polyoxyalkylene polyol (polyether polyol) with a polycarboxylic acid anhydride and an alkylene oxide.
The number average molecular weight of the macropolyol is, for example, 350 to 20000, preferably 600 to 15000.

These macropolyols can be used alone or in combination of two or more. Preferably, polyether polyol and polyoxyalkylene polyester block copolymer polyol are used.
The active hydrogen group-containing compounds can be used alone or in combination of two or more. Preferably, a macropolyol is used alone, or a low molecular weight polyol and a macropolyol are used in combination.

When the low molecular weight polyol and the macropolyol are used in combination, the blending ratio of the low molecular weight polyol is, for example, 1 to 200 parts by weight, preferably 5 to 150 parts by weight with respect to 100 parts by weight of the macropolyol.
And the polyurethane resin composition for pressure-sensitive sensors of this invention is obtained by preparing the above-mentioned polyisocyanate and an active hydrogen group containing compound.

In the polyurethane resin composition for pressure-sensitive sensors of the present invention, the aromatic ring concentration is preferably 15 to 25% by weight, more preferably based on the polyurethane resin composition (total amount of polyisocyanate and active hydrogen group-containing compound). Is 17 to 23% by weight.
If the aromatic ring concentration of the polyurethane resin composition is within the above range, the photoelastic constant can be increased.

The aromatic ring concentration is calculated with the molecular weight of the aromatic ring being 78 (g / mol).
And the polyurethane molding for pressure sensors of the present invention is obtained by reacting a polyisocyanate with an active hydrogen group-containing compound from the polyurethane resin composition for pressure sensors of the present invention thus obtained. It can be obtained by curing and molding the product.

In order to react the polyisocyanate and the active hydrogen group-containing compound, for example, a known molding method such as a one-shot method or a prepolymer method can be used.
In the one-shot method, for example, a polyisocyanate and an active hydrogen group-containing compound have an isocyanate index (a value obtained by multiplying the ratio of the isocyanate group concentration to the active hydrogen group concentration by 100, NCO concentration / active hydrogen group concentration × 100), For example, it is formulated (mixed) to be 70 to 400, preferably 80 to 150, and injected into a mold, for example, 0 ° C. to 250 ° C., preferably room temperature (20 ° C.) to 150. The curing reaction is carried out at 0 ° C., for example, for 1 minute to 7 days, preferably for 10 minutes to 2 days.

  In this curing reaction, a urethanization catalyst can be added. Examples of the urethanization catalyst include tin-based catalysts (for example, tin octylate), lead-based catalysts (for example, lead octylate), bismuth-based catalysts, organometallic catalysts, amine-based catalysts, and the like. May be a lead-based catalyst or a tin-based catalyst, and more preferably a lead-based catalyst from the viewpoint of obtaining a high photoelastic constant.

The blending ratio of the urethanization catalyst is, for example, 0.001 to 2.0 parts by weight, preferably 0.005 to 1.0 parts by weight with respect to 100 parts by weight of the polyisocyanate.
Moreover, the above-mentioned curing reaction can also be carried out in the presence of a known solvent.
And after inject | pouring into a shaping | molding die and making it harden | cure-react, if it demolds, the polyurethane molding for pressure sensitive sensors shape | molded by the predetermined shape can be obtained.

  In the prepolymer method, for example, first, a polyisocyanate and a part of an active hydrogen group-containing compound (for example, a macropolyol) are reacted to synthesize an isocyanate group-terminated prepolymer having an isocyanate group at the molecular end. Next, the obtained isocyanate group-terminated prepolymer and the remainder of the active hydrogen group-containing compound (chain extender: for example, low molecular weight polyol) are reacted to cause a curing reaction.

  In order to synthesize an isocyanate group-terminated prepolymer, polyisocyanate and a part of the active hydrogen group-containing compound have an isocyanate index (NCO concentration / active hydrogen group concentration × 100) of, for example, 110 to 2000, preferably 150. It is formulated (mixed) to be ~ 1000, and is, for example, room temperature to 150 ° C, preferably 40 to 120 ° C, for example, 0.5 to 18 hours, preferably 2 to 10 hours in a reaction vessel. , React.

The aforementioned isocyanate group-terminated prepolymer can be synthesized in the presence of a known solvent.
Further, after the synthesis of the above-mentioned isocyanate group-terminated prepolymer, unreacted polyisocyanate may be removed by a removal method such as a distillation method such as a thin film distillation method, for example, an extraction method such as a liquid-liquid extraction method. it can.

The obtained isocyanate group-terminated prepolymer has an isocyanate equivalent of, for example, 80 to 2000, preferably 100 to 1000.
Next, in order to react the obtained isocyanate group-terminated prepolymer with the remainder of the active hydrogen group-containing compound, the isocyanate group-terminated prepolymer and the remainder of the active hydrogen group-containing compound are reacted with the isocyanate index (NCO concentration / activity). The hydrogen group concentration x 100) is, for example, formulated (mixed) so as to be 50 to 200, preferably 75 to 125, and injected into a mold, for example, 0 to 60 ° C., preferably room temperature to 50 For example, the curing reaction is performed at 5 ° C. for 5 minutes to 72 hours, preferably 1 to 24 hours.

Also in this curing reaction, the same urethanization catalyst as described above can be added at the same mixing ratio as described above. Moreover, this hardening reaction can also be implemented in presence of a well-known solvent.
And after inject | pouring into a shaping | molding die and making it harden | cure-react, if it demolds, the polyurethane molding for pressure sensitive sensors shape | molded by the predetermined shape can be obtained.

The polyurethane molded body for a pressure-sensitive sensor of the present invention can generate birefringence in light passing through the molded body (for example, laser light) by photoelasticity, that is, generation of stress.
Specifically, the pressure-sensitive sensor polyurethane molded product has a maximum photoelastic constant at −20 to 60 ° C. of, for example, 1000 × 10 ⁻¹² Pa ⁻¹ or more, preferably 2000 × 10 ⁻¹² Pa ^{−. 1} or more, more preferably 3000 × 10 ⁻¹² Pa ⁻¹ or more, and usually 100000 × 10 ⁻¹² Pa ⁻¹ or less. That is, the photoelastic constant may be within the above-described range, for example, the peak top (maximum value) in the temperature range of -20 to 60 ° C. It does not have to be.

The photoelastic constant of the polyurethane molded body for pressure-sensitive sensors is “Mitsuo Tsukiji, Hiroyuki Takawa, Yoshiro Tanabe“ Development of Photoelastic Constant Measurement System for Optical Films ”, Journal of Precision Society 73, 253-258 (2007). ”In accordance with the description of“ Method for Measuring Photoelastic Constant ”.
When the photoelastic constant is in the above-described range, excellent photoelasticity can be ensured.
Moreover, the glass transition temperature of the polyurethane molding for pressure sensors is -10-35 degreeC, for example, Preferably, it is -5-30 degreeC, More preferably, it is 0-25 degreeC.

The glass transition temperature of the pressure-sensitive sensor polyurethane molded body can be obtained by measuring the temperature dispersion mode at a frequency of 10 Hz using a dynamic viscoelasticity measuring device.
When the glass transition temperature is in the above range, the photoelastic constant can be increased.
In addition, such polyurethane resin compositions or polyurethane molded articles for pressure-sensitive sensors may include, for example, an antifoaming agent, a plasticizer, a leveling agent, a matting agent, a flame retardant, a thixotropic agent, and a tackifier. Add known additives such as additives, thickeners, lubricants, antistatic agents, surfactants, reaction retarders, dehydrating agents, antioxidants, ultraviolet absorbers, hydrolysis inhibitors, weathering stabilizers, etc. Can do.

FIG. 1 shows a plan view of an embodiment of the touch panel according to the present invention (a mode in which a light emitting portion and a light receiving portion are arranged outside a polyurethane molded body for a pressure sensitive sensor).
Next, a pressure-sensitive sensor including the above-described polyurethane molded body for a pressure-sensitive sensor and a touch panel including the pressure-sensitive sensor will be described with reference to FIG. In FIG. 1, the vertical direction on the paper surface is “vertical direction” and the horizontal direction on the paper surface is “horizontal direction”.

In FIG. 1, the touch panel 1 includes a pressure sensor 2 and a processing unit 3 that processes a signal sensed by the pressure sensor 2.
The pressure sensor 2 includes a pressure-sensitive sensor polyurethane molded body 4 and a stress generation detection unit 15 for detecting the generation of stress in the pressure-sensitive sensor polyurethane molded body 4.
The pressure-sensitive sensor polyurethane molded body 4 is formed into a sheet shape by a molding die (casting die) having a predetermined shape, or formed into a sheet shape having a predetermined shape by cutting after demolding. Specifically, the pressure-sensitive sensor polyurethane molded body 4 is formed in a substantially rectangular flat sheet shape in plan view. The thickness of the pressure-sensitive sensor polyurethane molded body 4 is not particularly limited, and is, for example, 0.005 to 50 mm, preferably 0.01 to 10 mm, and more preferably 0.1 to 5 mm.

The stress generation detection unit 15 includes an optical sensor, and includes a pair of light emitting units 5 and a light receiving unit 8 provided so as to sandwich both sides of the pressure-sensitive sensor polyurethane molded body 4.
The light emitting section 5 is disposed on one side in the longitudinal direction of the pressure-sensitive sensor polyurethane molded body 4, and a plurality of longitudinal light emitting sections 6 arranged in parallel along the lateral direction, and the lateral direction in the pressure-sensitive sensor polyurethane molded body 4. A plurality of horizontal light emitting units 7 arranged on one side and arranged in parallel along the vertical direction are provided.

The vertical light emitting unit 6 includes a first light emitting unit 5A, a second light emitting unit 5B, and a third light emitting unit 5C that are sequentially arranged from the other side in the horizontal direction toward the one side. The lateral light emitting unit 7 includes a fourth light emitting unit 5D, a fifth light emitting unit 5E, and a sixth light emitting unit 5F, which are sequentially arranged from one side in the vertical direction to the other side.
The light-receiving unit 8 is provided corresponding to each light-emitting unit 5, and is arranged to face the vertical-side light-emitting unit 6, the horizontal-side light-emitting unit 7, and the pressure-sensitive sensor polyurethane molded body 4. The unit 9 and the lateral light receiving unit 10 are provided.

A plurality of vertical light receiving portions 9 are arranged in parallel along the horizontal direction on the other vertical side of the polyurethane molded body 4 for pressure-sensitive sensors. That is, the vertical light receiving unit 9 corresponds to the first light emitting unit 5A, the second light emitting unit 5B, and the third light emitting unit 5C, and is sequentially arranged from the other side in the horizontal direction toward the one side. The second light receiving unit 8B and the third light receiving unit 8C are provided.
A plurality of lateral light receiving portions 10 are arranged in parallel along the longitudinal direction on the other lateral side of the polyurethane molded body 4 for pressure-sensitive sensors. That is, the lateral light receiving unit 10 corresponds to the fourth light emitting unit 5D, the fifth light emitting unit 5E, and the sixth light emitting unit 5F, and is sequentially arranged from one side in the vertical direction toward the other side. The fifth light receiving unit 8E and the sixth light receiving unit 8F are provided.

  Thereby, in the polyurethane molding 4 for pressure-sensitive sensors, on the line which connects each light emission part 5 and each light-receiving part 8, More specifically, the line which connects the vertical side light emission part 6 and the vertical side light-receiving part 9, and horizontal On the intersection with the line connecting the side light emitting unit 7 and the side light receiving unit 10, a plurality of (9) detection units (in solid and broken circles) for detecting the contact with a finger or the like 11 (11a to 11i) is defined.

  In addition, the pressure sensor 2 is provided with a plurality (four) of polarizing films 13 interposed between the pressure-sensitive sensor polyurethane molded body 4 and the light emitting unit 5 and the light receiving unit 8. Specifically, each polarizing film 13 is formed between the pressure-sensitive sensor polyurethane molded body 4 and the vertical light emitting section 6, between the pressure sensitive sensor polyurethane molded body 4 and the horizontal light emitting section 7, and the pressure sensitive sensor. Are disposed between the polyurethane molded body 4 for use and the vertical light receiving portion 8 and between the polyurethane molded body 4 for pressure sensitive sensor and the lateral light emitting portion 9.

  The processing unit 3 includes, for example, an LED 14 and the like, and is electrically connected to each light receiving unit 8 via the wiring 12. The processing unit 3 forms a polyurethane molding for a pressure-sensitive sensor from a birefringence detection signal of the laser light detected by the vertical light receiving unit 9 and a birefringence detection signal of the laser light detected by the horizontal light receiving unit 10. It is determined which detection unit 11 of the body 4 is in contact with the finger and displayed on the LED 14.

Next, a method of sensing a stress occurrence location of the pressure-sensitive sensor polyurethane molded body 4 using the touch panel 1 will be described.
First, in the stress generation detection unit 15, laser light is emitted from the light emitting unit 5 toward the light receiving unit 8 so as to pass through the inside of the pressure-sensitive sensor polyurethane molded body 4. At this time, in the pressure-sensitive sensor polyurethane molded body 4, since no birefringence is generated in the laser light, the laser light is blocked by the polarizing film 13 and is not received by the light receiving unit 8.

Next, a finger is brought into contact with the detection unit 11 (11a, solid line), and stress is generated in the detection unit 11.
Then, since birefringence occurs in the detection unit 11, the birefringent laser light is received by the light receiving unit 8.
More specifically, the first light receiving unit 8A and the fourth light receiving unit 8D arranged on the other side in the vertical direction and the other side in the horizontal direction of the detection unit 11a detect the presence or absence of birefringence in the detection unit 11a.

Subsequently, an electrical signal based on the detection of birefringence of the first light receiving unit 8A and the fourth light receiving unit 8D is input to the processing unit 3, whereby the processing unit 3 has the detection unit 11a at which the stress is generated. Detect that.
Further, with respect to the other detection units 11 (11b to 11i), the stress occurrence location is detected in the same manner as described above.

The pressure-sensitive sensor polyurethane molded body 4 has excellent photoelasticity and further excellent moisture resistance, water resistance, electrical noise resistance, and electromagnetic wave resistance while being lightened and reduced in weight. . That is, even when the pressure sensitive sensor polyurethane molded body 4 is touched with a wet finger, it is possible to effectively prevent the occurrence of erroneous detection of the stress generation location.
Therefore, in the pressure-sensitive sensor 2 including the pressure-sensitive sensor polyurethane molded body 4, the stress generation location in the pressure-sensitive sensor polyurethane molded body 4 is reliably specified by stress strain sensing while reducing the weight and weight. be able to.

As a result, the touch panel 1 including the pressure-sensitive sensor 2 can achieve reliable sensing while reducing the weight and weight of the device.
In the above description, the light emitting unit 5 and the light receiving unit 8 are both provided outside the pressure-sensitive sensor polyurethane molded body 4 in a plan view. However, the arrangement is not particularly limited. For example, FIG. As shown in FIG. 2, it can also be provided inside the polyurethane molded body 4 for pressure-sensitive sensors.

  In FIG. 2, a mirror 16 is provided at the peripheral end of the pressure-sensitive sensor polyurethane molded body 4. The mirror 16 is arranged adjacent to the outside in the longitudinal direction and the outside in the lateral direction of the polyurethane molded body 4 for the pressure sensitive sensor, and is inclined to the outside by approximately 45 degrees as it goes downward, and the upper mirror surface 19 is provided with a lower mirror surface 20 that is continuous with the lower end of 19 and is inclined inward at approximately 45 degrees toward the lower side.

The light-emitting portion 5 is disposed below the pressure-sensitive sensor polyurethane molded body 4 with a space between the lower mirror surface 19 and the inner side (the other side in the vertical direction and the other side in the horizontal direction, see FIG. 1).
The light receiving unit 8 is disposed on the lower side of the pressure-sensitive sensor polyurethane molded body 4 so as to face the lower mirror surface 19 and on the inner side (vertical one side and horizontal one side, see FIG. 1) with the polarizing plate 13 interposed therebetween. ing.

In this touch panel 1, when a finger is brought into contact with the detection unit 11 and stress is generated in the detection unit 11, birefringence occurs in the detection unit 11, and thus the birefringent laser light is reflected by the mirror 16. Thereafter, the light is received by the light receiving unit 8. As a result, the processing unit 3 (see FIG. 1, not shown in FIG. 2) detects a stress generation location in the detection unit 11.
In the touch panel 1, the light emitting unit 5 and the light receiving unit 8 are provided inside the polyurethane molded body 4 for the pressure sensitive sensor, so that the device can be made compact.

  In the above description of FIG. 1 and FIG. 2, the polyurethane molded body for pressure sensitive sensor of the present invention is used for the touch panel 1 including the pressure sensitive sensor 2, but its use is not particularly limited and is not shown. However, it can also be used for an optical shutter, an aberration correction element (lens aberration correction element), and the like.

The present invention will be specifically described below with reference to examples and comparative examples.
In addition, the details of the abbreviations described in Examples and Comparative Examples and Tables 1 to 5 are described.
Triol 8500: Polypropylene triol, initiator: glycerin, number average molecular weight 8500, hydroxyl value 20 mgKOH / g
Triol 5000: Polypropylene triol, initiator: glycerin, number average molecular weight 5000, hydroxyl value 34 mgKOH / g
Triol 3000: Polypropylene triol, initiator: glycerin, number average molecular weight 3000, hydroxyl value 56 mgKOH / g
Triol 1500: Polypropylene triol, initiator: glycerin, number average molecular weight 1500, hydroxyl value 112 mgKOH / g
Triol 1000: Polypropylene triol, initiator: glycerin, number average molecular weight 1000, hydroxyl value 168 mgKOH / g
Triol 700: Polypropylene triol, initiator: glycerin, number average molecular weight 700, hydroxyl value 240 mgKOH / g
Triol 300: Polypropylene triol, initiator: glycerin, number average molecular weight 300, hydroxyl value 560 mgKOH / g
Diol 1000: Polypropylene diol, initiator: ethylene glycol, number average molecular weight 1000, hydroxyl value 110 mg KOH / g
Diol 400: polypropylene diol, initiator: ethylene glycol, number average molecular weight 400, hydroxyl value 280 mgKOH / g
1,4-BG: 1,4-butylene glycol, hydroxyl value 1245 mgKOH / g
DPG: Dipropylene glycol, hydroxyl value 836 mgKOH / g
3P-56M: Polyoxyalkylene polyester block copolymer polyol, average number of functional groups: about 3, hydroxyl value: 56 mgKOH / g
1,3-H ₆ XDI: 1,3-bis (isocyanatomethyl) cyclohexane 1,3-XDI: 1,3-xylylene diisocyanate H ₁₂ MDI: dicyclohexylmethane diisocyanate TDI-100: 2,4-tri Diisocyanate TDI-80: Isomeric mixture of 2,4- and 2,6-tolylene diisocyanate (2,4 / 2,6 isomer mixing ratio 80:20)
TDI-65: isomer mixture of 2,4- and 2,6-tolylene diisocyanate (2,4 / 2,6 isomer mixture ratio 65:35)
4,4'-MDI: 4,4'-diphenylmethane diisocyanate 2,2'-MDI: 2,2'-diphenylmethane diisocyanate prepolymer XDI-1: isocyanate group terminal obtained by reaction of triol 3000 and 1,3-XDI Prepolymer (mixing ratio: 50 parts by weight / 29.37 parts by weight)
Prepolymer PH-1: Isocyanate group-terminated prepolymer obtained by reaction of triol 3000 and 4,4′-MDI (mixing ratio: 50 parts by weight / 39.3 parts by weight)
Lead octylate: trade name “24% hexoate lead”, catalyst, tin octylate manufactured by Toei Chemical Co., Ltd .: trade name “Dabco T-9”, catalyst, BYK-070 manufactured by Air Products and Chemicals Co., Ltd .: Foam-breaking polymer and poly Siloxane solution, Examples 1 to 19, 24 to 26 and Comparative Examples 1 to 3 manufactured by Big Chemie Japan
Based on Table 1 to Table 5, a polyisocyanate, an active hydrogen group-containing compound, a catalyst (and an antifoaming agent blended as necessary) were formulated, and Examples 1 to 19, 24 to 26, and Comparative Examples 1 to 3 was formed as a pressure sensitive sensor polyurethane molded body.

Specifically, first, a polyisocyanate, an active hydrogen group-containing compound, a catalyst (and an antifoaming agent blended as necessary) are mixed into a mixing pot at a predetermined temperature (liquid temperature before mixing). The mixture was added at a ratio to become an isocyanate index, and defoamed for 30 seconds under reduced pressure while mixing.
Thereafter, this was poured into a casting mold and cured at 100 ° C. for 24 hours. As a result, a polyurethane molded body for a pressure-sensitive sensor having a thickness of 2.0 mm was obtained. The casting mold is formed of two flat metal plates facing in the thickness direction and a piece-like spacer sandwiched between the peripheral ends (gap).

Examples 20 and 21
First, prepolymer XDI-1 was prepared.
That is, prepolymer XDI-1 was prepared by blending 29.37 parts by weight of 1,3-XDI and 50 parts by weight of triol 3000 (isocyanate index: 625) and reacting at 80 ° C. for 5 hours.

Then, based on Table 4, prepolymer XDI-1, an active hydrogen group-containing compound, a catalyst, and an antifoaming agent were formulated and cured in the same manner as in Example 1. A polyurethane molded body for pressure sensor was molded.
Examples 22 and 23
First, prepolymer PH-1 was prepared.

That is, the prepolymer PH-1 was prepared by blending 3,9.3 parts by weight of 4,4′-MDI and 50 parts by weight of triol 3000 (isocyanate index: 629) and reacting at 80 ° C. for 5 hours. .
Then, based on Table 4, prepolymer PH-1, an active hydrogen group-containing compound, a catalyst, and an antifoaming agent were formulated and cured in the same manner as in Example 1 to thereby improve the sensitivity of Examples 22 and 23. A polyurethane molded body for pressure sensor was molded.

(Evaluation)
(1) Photoelastic constant The photoelastic constants of the polyurethane moldings for pressure-sensitive sensors at −20 to 60 ° C. in each of the examples and comparative examples are described in “For optical films” by Mitsuo Tsukiji, Hiroyuki Takawa, Yoshiro Tanabe. Measurement was performed according to the description of “Photoelastic constant measurement method” in “Development of photoelastic constant measurement system”, Journal of Precision Society 73, 253-258 (2007), and the maximum value was obtained. The results are shown in Tables 1-5.
(2) Glass transition temperature The glass transition temperature (Tg) of the polyurethane molded body for pressure-sensitive sensors of each Example and each Comparative Example was measured using a dynamic viscoelasticity measuring device (VES-F-III, VISCO-ELASTICSPECTROMETER, Iwamoto Seisakusho). A sample piece cut into a strip shape having a length of 10.0 cm, a width of 5.0 mm, and a thickness of 2.0 mm, a temperature rise rate of 3 ° C./min, a frequency of 10 Hz, and an amplitude of ± 0.01 mm. Measurement was performed in a dispersion mode, and the peak value of tan δ of the obtained data was calculated. The results are shown in Tables 1-5.
(3) Appearance The degree of transparency of the pressure-sensitive sensor polyurethane molded body of each Example and each Comparative Example was observed with the naked eye. The results are shown in Tables 1-5.

1 Touch panel 2 Pressure sensor 4 Polyurethane molded body for pressure sensor

Claims (7)

A polyurethane resin composition used for a pressure-sensitive sensor,
Polyisocyanate,
A polyurethane resin composition for pressure-sensitive sensors, comprising an active hydrogen group-containing compound having an average active hydrogen group value of 30 to 550 mgKOH / g.   The polyurethane resin composition for pressure-sensitive sensors according to claim 1, wherein the aromatic ring concentration is 15 to 25% by weight. It is obtained by molding the polyurethane resin composition according to claim 1 or 2,
A polyurethane molded article for pressure-sensitive sensors, characterized by having photoelasticity. The polyurethane molded product for pressure-sensitive sensors according to claim 3, wherein the maximum value of the photoelastic constant at -20 to 60 ° C is 1000 x 10 ^-12 Pa ^-1 or more.   The polyurethane molded article for pressure-sensitive sensors according to claim 3 or 4, wherein the glass transition temperature is -10 to 35 ° C.   A pressure-sensitive sensor comprising the polyurethane molded body for a pressure-sensitive sensor according to claim 3.   A touch panel comprising the pressure-sensitive sensor according to claim 7.

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