JP2018040978A - Sound absorbing material with film and sound absorbing material production method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently produce a sound absorbing material with film.SOLUTION: A film is formed of an urethane prepolymer having at least one of an allyl ether group, a vinyl ether group and an acrylate group as a terminal functional group and polythiol having a thiol group on the surface of a base formed of a synthetic resin porous body. The urethane prepolymer having the terminal functional group and the polythiol having the thioL group are irradiated with light to cause an ene-thiol reaction between the terminal functional group and the thiol group, and are cured. Thereby, a sound absorbing material with film can be produced by irradiation with ultraviolet rays without performing a drying step, a heating step and the like, and production efficiency is improved. In a curing reaction utilizing the ene-thiol reaction, there is no curing failure due to existence of oxygen, which does not need to block the oxygent. Because of this, a sound absorbing material with film can be efficiently produced.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a sound-absorbing material with a coating provided with a base made of a synthetic resin porous body and a coating formed on at least a part of the surface of the base, and a method for producing the sound-absorbing material.

  Synthetic porous materials such as polyurethane foam have good sound absorption characteristics, and are therefore used as mechanical products such as compressors, motors, pumps, printers, acoustic products such as speakers, and sound absorbing materials for construction machines. However, since only the synthetic resin porous body has insufficient sound absorption characteristics in the low frequency range, as described in the following patent document, a film is formed on the surface of the synthetic resin porous body, and the membrane vibration due to the film is used. Therefore, sound absorbing materials having sound absorbing characteristics in a wide frequency range including a low frequency range have been developed.

JP-A-6-226897 Japanese Patent No. 3388683 Japanese Patent No. 5542324 JP 2009-63763 A

  By using the technique described in the above patent document, it is possible to manufacture a sound absorbing material having sound absorbing characteristics in a wide frequency range. However, the techniques described in the above patent documents have various problems. Specifically, in the technique described in Patent Literature 1, an adhesive material made of urethane resin is formed as a film on the surface of the synthetic resin porous body. In this technique, after the adhesive material is transferred to the surface of the synthetic resin porous body, a drying step is required in which drying is performed for 1 minute in an environment of 80 ° C. in order to remove the solvent and the like. Moreover, in order to acquire the adhesiveness of a synthetic resin porous body and an adhesive material, it is necessary to leave for one day. In the technique described in Patent Document 2, a polyethylene film or the like is laminated as a film on the surface of the synthetic resin porous body. This technique requires a hot pressing process at 125 ° C. for 90 seconds in order to laminate a polyethylene film or the like on the surface of the synthetic resin porous body. Moreover, in the technique of the said patent document 3, a membrane | film | coat is formed by heat-melting the surface of a synthetic resin porous body. In this technique, a heating step of 280 to 400 ° C. is required in order to heat-melt the surface of the synthetic resin porous body. In the technique described in Patent Document 4, a film is formed by transferring and curing an ultraviolet curable elastomer on the surface of the metal fiber sheet, not the synthetic resin porous body. In this technology, since the ultraviolet curable elastomer causes poor curing due to the presence of oxygen, the ultraviolet ray is blocked in a situation where oxygen is blocked, for example, a situation where the ultraviolet curable elastomer is sandwiched between films, or a situation where nitrogen is filled. It is necessary to irradiate the cured elastomer with ultraviolet rays. As described above, in the technique described in the above-mentioned patent document, various steps are required to manufacture the sound absorbing material, and the efficiency is poor. This invention is made | formed in view of such a situation, and makes it a subject to provide the sound-absorbing material with a film | membrane which can be manufactured efficiently.

  The sound-absorbing material with a film of the present invention comprises a base composed of a synthetic resin porous body, a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group, and a polythiol having a thiol group. An allyl ether group, a vinyl ether group, and an acrylate of the urethane prepolymer in a total equivalent number of thiol groups of the polythiol, and a film formed on at least a part of the surface of the substrate. The ratio with respect to the total number of equivalents of at least one group is 0.7 to 2.3.

  In addition, the method for producing a sound absorbing material of the present invention includes a raw material comprising a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group, and a polythiol having a thiol group. An adhesion step of attaching to at least a part of the surface of a substrate made of a body, and an irradiation step of irradiating light to the raw material attached in the attachment step, and producing a sound absorbing material with a film by a photopolymerization reaction And

  In the sound-absorbing material with a film and the method for producing the sound-absorbing material of the present invention, synthesis is performed by using a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group, and a polythiol having a thiol group. A film is formed on the surface of the substrate made of the porous resin body. A urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group, and a polythiol having a thiol group are obtained by irradiating light with at least one of an allyl ether group, a vinyl ether group, and an acrylate group. An enethiol reaction occurs between one and the thiol group and cures. Thereby, it becomes possible to manufacture a sound-absorbing material with a film by irradiating ultraviolet rays without performing steps such as a drying step and a heating step, and the manufacturing efficiency is improved. In addition, in the curing reaction using the enethiol reaction, there is no curing failure due to the presence of oxygen, so there is no need to block oxygen. For this reason, according to the sound-absorbing material with a film of this invention and the manufacturing method of a sound-absorbing material, it becomes possible to manufacture a sound-absorbing material with a film efficiently.

The blending amount (parts by weight) of the prepolymer as the raw material of the film of the sound absorbing material with film of Examples 1 to 6, the polythiol (molar ratio) as the raw material, and the physical property evaluation of the sound absorbing material with film of Examples 1 to 6 It is a table | surface which shows. The blending amount (parts by weight) of the prepolymer as a raw material of the film of the sound absorbing material with a film of Examples 7 to 11, the polythiol (molar ratio) as a raw material, and the physical property evaluation of the sound absorbing material with a film of Examples 7 to 11 It is a table | surface which shows. Compounding amount (parts by weight) of prepolymer as a raw material of the film of the sound absorbing material with a film of Comparative Examples 1 to 7, polythiol (molar ratio) as a raw material, and physical properties evaluation of the sound absorbing material with a film of Comparative Examples 1 to 7 It is a table | surface which shows. It is a table | surface which shows the compounding quantity (weight part) of the raw material for manufacturing prepolymer AD shown to FIGS. It is a table | surface which shows the compounding quantity (weight part) of the raw material for manufacturing the prepolymers EH shown to FIGS. It is a graph which shows the sound absorption rate with respect to the frequency of a sound-absorbing material with a film, and a sound-absorbing material without a film.

  The “sound-absorbing material with a film” described in the present invention includes a base made of a synthetic resin porous body, a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group, and a thiol group. And a film formed on at least a part of the surface of the substrate using a composition comprising polythiol. The ratio of the total equivalent number of thiol groups possessed by polythiol to the total equivalent number of allyl ether groups, vinyl ether groups and acrylate groups possessed by the urethane prepolymer is 0.7 to 2.3. .

  In addition, the “sound absorbing material manufacturing method” described in the present invention includes a raw material comprising a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group, and a polythiol having a thiol group. And manufacturing a sound-absorbing material with a film by a photopolymerization reaction, which includes an attaching step of attaching to at least a part of the surface of a substrate made of a synthetic resin porous body and an irradiation step of irradiating light to the raw material attached in the attaching step To do.

  The base of the sound absorbing material with a film is composed of a synthetic resin porous body. The synthetic resin porous body is not particularly limited, but is preferably an elastic foam in which many cells are formed by foaming, and examples thereof include polyurethane foam and polyolefin foam.

  Further, a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group and an acrylate group as a terminal functional group is obtained by adding an allyl ether group, a vinyl ether group and an acrylate group to a urethane prepolymer synthesized from a polyol and a polyisocyanate. And a compound having at least one of Incidentally, if the weight average molecular weight of the urethane prepolymer is too high or too low, the followability of the coating to the substrate is deteriorated. For this reason, it is preferable that the weight average molecular weights of the said urethane prepolymer are 2000-30000. If it says further, it is preferable that it is 2500-25000, and it is especially preferable that it is 3000-21000.

  The “polyisocyanate” used for the synthesis of the urethane prepolymer is a compound having two or more isocyanate groups in one molecule, and may be any compound that is usually employed as a raw material for the urethane prepolymer. For example, aromatic isocyanate, aliphatic isocyanate, alicyclic isocyanate, etc. are mentioned. Examples of the aromatic isocyanate include tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), polymeric MDI (crude MDI), xylylene diisocyanate, 1,5-naphthalene diisocyanate, and the like. Examples of the aliphatic isocyanate include hexamethylene diisocyanate, isopropylene diisocyanate, and methylene diisocyanate. Examples of the alicyclic isocyanate include cyclohexane-1,4-diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate (hydrogenated MDI), and the like. A combination of one or more of these various polyisocyanates can be used as a raw material for the urethane prepolymer.

  The “polyol” used for the synthesis of the urethane prepolymer is a compound having two or more hydroxyl groups in one molecule, and may be any compound that is usually employed as a raw material for the urethane prepolymer. For example, a polyester polyol, a polyether polyol, etc. are mentioned. Some polyester polyols are obtained by a condensation reaction between a polyhydric alcohol and a polycarboxylic acid. Examples of the polyhydric alcohol include ethylene glycol, propylene glycol, butanediol, butylene glycol, glycerin, trimethylolpropane, and the like, and these can be used alone or in combination of two or more. Examples of the polyvalent carboxylic acid include glutaric acid, adipic acid, maleic acid, terephthalic acid, and isophthalic acid, and these can be used alone or in combination of two or more. Furthermore, the polyester polyol obtained by ring-opening condensation of caprolactone, methylvalerolactone, etc. is mentioned.

  Examples of polyether polyols include addition polymerization of oxides such as ethylene oxide, propylene oxide, trimethylene oxide, and butylene oxide to polyhydric alcohols such as ethylene glycol, propylene glycol, diethylene glycol, glycerin, trimethylolpropane, and sorbitol. Can be mentioned. It is possible to use one or a combination of two or more of these various polyols as a raw material for the urethane prepolymer.

  Moreover, it is preferable to use a catalyst in the synthesis | combination of the said urethane prepolymer. The catalyst is not particularly limited as long as it is normally employed as a raw material for the urethane prepolymer, and examples thereof include amine-based catalysts and organometallic catalysts. Examples of the amine catalyst include triethylenediamine, diethanolamine, dimethylaminomorpholine, N-ethylmorpholine, and the like. Examples of the organometallic catalyst include star octoate, dibutyltin dilaurate, lead octenoate, potassium octylate and the like. A combination of one or more of these various catalysts can be used as a raw material for the urethane prepolymer.

  The compound having at least one of allyl ether group, vinyl ether group, and acrylate group to be added to the synthesized urethane prepolymer may be any compound that can be added to the isocyanate group of the urethane prepolymer. , Hydroxyethyl allyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxyethyl acrylate and the like. In order to increase the reaction activity, a monofunctional active hydrogen compound is preferable, and it is preferable that the double bond is in the vicinity of both ends of the polymer.

  Examples of the polythiol that undergoes an enethiol reaction with the urethane prepolymer include esters of mercaptocarboxylic acid and a polyhydric alcohol, aliphatic polythiols, and aromatic polythiols. Examples of the aliphatic polythiol and aromatic polythiol include ethanedithiol, propanedithiol, hexamethylenedithiol, decamethylenedithiol, tolylene-2,4-dithiol, xylenedithiol and the like.

  In the ester of mercaptocarboxylic acid and polyhydric alcohol, examples of mercaptocarboxylic acid include thioglycolic acid and mercaptopropionic acid, and examples of polyhydric alcohol include ethylene glycol, propylene glycol, 1,4-butanediol, , 6-hexanediol, glycerin, trimethylolpropane, pentaerythritol, sorbitol and the like. Among these, an ester of a mercaptocarboxylic acid and a polyhydric alcohol is preferable in terms of low odor. Specifically, for example, trimethylolpropane tris (3-mercaptopropionate), pentaerythritol tetrakis (3 -Mercaptopropionate), tetraethylene glycol bis (3-mercaptopropionate), dipentaerythritol hexa (3-mercaptopropionate). In addition, it is possible to use what used together 1 type, or 2 or more types of those various polythiols as a raw material of enethiol reaction with the said urethane prepolymer.

  The urethane prepolymer having at least one of the above-mentioned allyl ether group, vinyl ether group and acrylate group as a terminal functional group and polythiol are mixed and irradiated with light, whereby at least one of the surface of the substrate is obtained by the enethiol reaction. It is possible to form a film on the part. In addition, by using a thiol having an average functional group number of thiol groups of 2.5 or more as the polythiol described above, it is possible to obtain a film having a suitable followability to the substrate.

  In addition, the amount of thiol groups that are reacted with a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group has the same number of all thiol groups as the urethane prepolymer. It is preferable that the ratio (ene / thiol ratio) of at least one of allyl ether group, vinyl ether group and acrylate group is 0.7 to 2.3. Furthermore, it is preferably 0.8 to 2.0, and particularly preferably 1.0. If the ene / thiol ratio is too large or too small, the followability of the film to the substrate may be reduced.

  Further, in order to effectively perform a photopolymerization reaction between at least one of allyl ether group, vinyl ether group, and acrylate group added to the urethane prepolymer and a thiol group, the blending raw material may contain a photopolymerization initiator. Is possible. Examples of the photopolymerization initiator include acetophenone-based, benzophenone-based, and thioxanthone-based compounds. As the acetophenone series, for example, 2,2-dimethoxy-2-phenylacetophenone, 1,1-dichloroacetophenone, 4- (1-t-butyldioxy-1-methylethyl) acetophenone, 2-methyl-1- [4- (Methylthio) phenyl] -2-morpholino-propan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, diethoxyacetophenone, 2-hydroxy-2-methyl- 1-phenylpropan-1-one, benzyldimethyl ketal, 4- (2-hydroxyethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1 -[4- (1-Methylvinyl) phenyl] propanone oligomer And the like.

  Examples of the benzophenone series include 4- (1-t-butyldioxy-1-methylethyl) benzophenone, 3,3 ′, 4,4′-tetrakis (t-butyldioxycarbonyl) benzophenone, and methyl o-benzoylbenzoate. 4-phenylbenzophenone, 4-benzoyl-4'-methyl-diphenyl sulfide, 3,3 ', 4,4'-tetra (t-butylperoxylcarbonyl) benzophenone, 2,4,6-trimethylbenzophenone, 4- Examples include benzoyl-N, N-dimethyl-N- [2- (1-oxo-2-propenyloxy) ethyl] benzenemethananium bromide, (4-benzoylbenzyl) trimethylammonium chloride, and the like. Examples of the thioxanthone series include 2,4-dimethylthioxanthone, 2,4-diisopropylthioxanthone, 2-chlorothioxanthone, 2-isopropylthioxanthone, 4-isopropylthioxanthone, 2,4-diethylthioxanthone, 2,4-dichloro. Examples include thioxanthone, 1-chloro-4-propoxythioxanthone, 2- (3-dimethylamino-2-hydroxy) -3,4-dimethyl-9H-thioxanthone-9-one mesochloride.

  The content of the photopolymerization initiator is preferably 0.01 to 5 parts by weight per 100 parts by weight of the urethane prepolymer, and more preferably 0.1 to 3 parts by weight. If the content of the photopolymerization initiator is too small, the photopolymerization initiation ability is insufficient, and the raw material is not rapidly polymerized, which is not preferable. On the other hand, if the content of the photopolymerization initiator is too large, polymerization is excessively promoted, the crosslinking density becomes too high, or the crosslinked structure is formed unevenly, which is not preferable.

  In addition, when a sound absorbing material with a film is formed using a raw material in which a urethane prepolymer having at least one of the above-mentioned allyl ether group, vinyl ether group, and acrylate group as a terminal functional group and polythiol is formed, The mixed raw material is applied with a predetermined film thickness on a film having good permeability. Next, a substrate made of a synthetic resin porous body is pressure-bonded onto the applied mixed raw material. Then, in the presence of air, the applied mixed raw material is irradiated with ultraviolet rays from below the film, whereby the mixed raw material is cured and a film is formed.

In addition, it is preferable that the irradiation amount of the ultraviolet-ray at the time of hardening a mixed raw material is 600-1800 mJ / cm < ² > (365 nm integrated light quantity). Moreover, when apply | coating a mixed raw material to a film, it is preferable to use coating apparatuses, such as a comma coater, a die coater, and a gravure coater. In particular, a die coater is preferably used because the viscosity of the viscous fluid can be adjusted by adjusting the temperature of the viscous fluid during application. In addition, it is preferable that the thickness of the film | membrane after hardening is 25-100 micrometers. When the thickness of the film after curing is too thick, the followability to the substrate is deteriorated. On the other hand, when the thickness of the cured film is too thin, good sound absorption characteristics cannot be expected.

  Further, the sound absorbing material is used for various objects, and the shapes of the objects are various. For this reason, a sound absorbing material is often used for corners, corners, etc., and in such a case, the sound absorbing material is greatly bent. At this time, the coating appropriately follows the substrate and bends together with the substrate. However, if the followability is low, the coating may be cracked or shaken. Thus, when a crack etc. arise in a membrane | film | coat, sound absorption performance will fall. For this reason, in order to index the followability of the film formed by the above method to the substrate, the following followability test was conducted. Specifically, a test piece is prepared by forming a film having a thickness of 50 μm on the surface of a urethane foam having a predetermined size (width 20 mm × length 150 mm × thickness 30 mm). Next, a double-sided tape is affixed to the back surface of the test piece, and is bonded to the outer peripheral surface of three different types of resin cylinders (φ160 mm, φ120 mm, φ90 mm). Then, after being left at room temperature for 24 hours, it is visually confirmed whether or not there are cracks, blurring, etc. in the film. At this time, in all three types of resin-made cylinders (φ160 mm, φ120 mm, φ90 mm) having different diameters, it is determined that the followability of the coating is good when there is no crack in the coating.

Further, when the sound absorbing material is used at the corners and corners, the film is greatly bent together with the base body, so that the film is desired to be easily stretched. For this reason, the elongation (%) of the film was measured based on JIS K 6400-5. Specifically, Taber abrasion (g) was measured according to the following conditions.
Test piece: No. 3 dumbbell shape (single film)
Testing machine; Shopper type tensile testing machine Tensile speed: 500 mm / min
Elongation (%) = {(l _B −l ₀ ) / l ₀ } × 100
l ₀ : Distance between gauge points = 40 mm
l _B : Length between gauge points during cutting (mm)
The elongation (%) is preferably 100% or more, and more preferably 150% or more.

Moreover, the sound absorbing performance of the sound absorbing material with a film was evaluated based on JIS A 1405-2 (normal incidence sound absorption coefficient) using the following tester.
Tester; Brüel & Kjær acoustic tester Acoustic tube; 4206 / 4206-T impedance tube basic configuration and transmission loss tube kit

  The following examples illustrate the present invention more specifically. However, the present invention is not limited to this embodiment, and can be implemented in various modes with various modifications and improvements based on the knowledge of those skilled in the art.

<Raw material and production of sound absorbing material with film>
The sound-absorbing material films of Examples 1 to 11 and the sound-absorbing material films of Comparative Examples 1 to 7 were produced from the raw materials having the formulations shown in FIGS. Below, the detail of each raw material is shown.

  Each of the “prepolymers” shown in FIGS. 1 to 3 is obtained by reacting raw materials having the composition (weight ratio) shown in FIG. 4 or FIG. 5 according to the following method.

  First, an amount shown in the figure is added to a 1 liter separable flask, and the amount shown in the figure is added while stirring the polyol while flowing nitrogen. After confirming that the contents are uniform, a catalyst (0.3 g of dibutyltin dilaurate (DBTDL)) is added. And it heats up slowly so that it may become 80-90 degreeC over 1 hour. Two hours after raising the temperature to the target temperature, the isocyanate group content is measured according to a method (polyurethane raw material aromatic isocyanate test method) based on JIS Z1603-1: 2007. And in prepolymer A, B, C, it confirms that the isocyanate group content rate is in the range of 4.0 to 5.0%. Moreover, in the prepolymer D, it confirms that the isocyanate group content rate is in the range of 2.0 to 3.0%. In the prepolymer E, it is confirmed that the isocyanate group content is in the range of 0.5 to 1.0%. In the prepolymer F, it is confirmed that the isocyanate group content is in the range of 0.2 to 1.0%. Moreover, in the prepolymer G, it confirms that the isocyanate group content rate exists in the range of 6.0-7.0%. In the prepolymer H, it is confirmed that the isocyanate group content is in the range of 0.1 to 0.5%. And when isocyanate group content rate is not in the range according to each prepolymer, reaction time is extended.

  After confirming that the isocyanate group content is within the range corresponding to each prepolymer, at least one of vinyl ether, acrylate and allyl ether is slowly dropped in the amount shown in the figure, and the reaction is carried out for 2 hours. . After 2 hours, the isocyanate group content is measured again according to the above method, and it is confirmed that the isocyanate group content is 0.5% or less. And each "prepolymer" shown to a figure is obtained on condition that the isocyanate group content rate is 0.5% or less.

  The theoretical molecular weight of “Prepolymer A” obtained as described above is 4129, the theoretical molecular weight of “Prepolymer B” is 4101, the theoretical molecular weight of “Prepolymer C” is 4157, “ The theoretical molecular weight of “Prepolymer D” is 2755, the theoretical molecular weight of “Prepolymer E” is 10581, the theoretical molecular weight of “Prepolymer F” is 20755, and the theoretical molecular weight of “Prepolymer G” is 1581. The theoretical molecular weight of “Prepolymer H” is 30755.

Polyol a: Polypropylene glycol (PPG), trade name: Actol D2000 (Mw: 2000), manufactured by Mitsui Chemicals, Inc. Polyol b: Polypropylene glycol (PPG), trade name: Actol D1000 (Mw: 1000), Polyol c manufactured by Mitsui Chemicals, Inc .; Polypropylene glycol (PPG), trade name: Sannix PP-200 (Mw: 200), manufactured by Sanyo Chemical Co., Ltd. • Polyol d; Polypropylene glycol (PPG), trade name: Preminol S4011 (Mw: 10000), manufactured by Asahi Glass Co., Ltd., polyisocyanate; TDI, trade name: Rupranate T-80 (Mw: 174.2), manufactured by BASF, vinyl ether; hydroxybutyl vinyl ether (Mw: 116.2), Japan Carbide Co., Ltd. Allyl A Le; hydroxyethyl allyl ether (Mw: 102.1), Nippon Emulsifier Co., Ltd. acrylate; 2-hydroxyethyl methacrylate (Mw: 130.1), manufactured by Nippon Shokubai Co., Ltd.

  Further, the total number of equivalents of at least one of an allyl ether group, a vinyl ether group and an acrylate group contained in 100 parts by weight of each “prepolymer” obtained as described above is calculated. And the equivalent number of the thiol group contained in the polythiol required as a raw material is calculated by multiplying the calculated equivalent number by the enethiol ratio (equivalent ratio) shown in FIGS. In addition, the compounding ratio of the polythiol shown in FIGS. 1-3 is the number-of-moles with respect to 100 weight part of said prepolymers. For this reason, the equivalent number of thiol groups is set to a ratio corresponding to the mixing ratio of thiols. Specifically, for example, in the case where the number of equivalents of thiol groups is A, in Example 1, since the molar ratio is 100 with respect to polythiol C, the number of equivalents of thiol groups of polythiol C is A. The In Example 2, since the molar ratio is 50 with respect to polythiol A and the molar ratio is 50 with respect to polythiol B, the number of equivalents of thiol groups of polythiol A is A / 2. The number of equivalents of the thiol group of B is A / 2. Then, the number of moles of each polythiol is calculated based on the number of equivalents of thiol groups of each polythiol and the number of functional groups of each polythiol. The calculated number of moles of each polythiol and 100 parts by weight of the prepolymer are weighed, heated to 80 ° C., and then mixed and stirred.

・ Polythiol A: functional group number 2, butanediol bisthiopropionate, trade name: BDTP (Mw: 266.4), manufactured by Sakai Chemical Co., Ltd. ・ Polythiol B: functional group number 3, trimethylolpropane tris, trade name: TMMP (Mw: 398.5), manufactured by SC Organic Chemical Co., Ltd., polythiol C; functional group number 4, pentaerythritol tetrakis, trade name: PMP (Mw: 488.6), manufactured by SC Organic Chemical Co., Ltd., polythiol D Functional group number 6, dipentaerythritol hexakis, trade name: DPMP (Mw: 783.0), manufactured by SC Organic Chemical Co., Ltd.

  In addition, the average functional group number of the thiol group with which each urethane prepolymer is reacted is shown in the column of “average functional group number” in FIGS. Further, the ratio of the total number of equivalents of all thiol groups to the total number of equivalents of one of the vinyl ether groups, allyl ether groups, and acrylate groups of each urethane prepolymer is shown as “ene / thiol ratio” in FIGS. It is shown in the column.

And the raw material mixed by the compounding ratio shown in FIGS. 1-3, ie, the mixed prepolymer and polythiol, is apply | coated by the film thickness of 50 micrometers on a release film with sufficient permeability | transmittance. Next, a urethane foam as a substrate is pressure-bonded onto the applied mixed raw material. In addition, what cut out the urethane foam shown below into a predetermined | prescribed size was used as a urethane foam of a base | substrate. And the ultraviolet-ray is irradiated to the mixed raw material by which the urethane foam was crimped | bonded from the downward direction of a release film. Thereby, the apply | coated mixed raw material hardens | cures and the sound-absorbing material with a film of Examples 1-11 and the sound-absorbing material with a film of Comparative Examples 1-7 are formed. In addition, the irradiation amount of the ultraviolet rays at the time of curing the mixed raw material is 600 mJ / cm ² (365 nm integrated light amount).
-Substrate (urethane foam): Soft polyurethane foam, manufactured by Inoac Corporation, density: 25 kg / m ³ (JIS K 7222), hardness (25% compression hardness): 127 N (JIS K 6400-2)

<Evaluation of physical properties of sound absorbing material with film>
The following performance was evaluated for the sound absorbing material with a film of Examples 1 to 11 and the sound absorbing material with a film of Comparative Examples 1 to 7 manufactured as described above. Specifically, by forming a film having a thickness of 50 μm on the surface of the above-described urethane foam (width 20 mm × length 150 mm × thickness 30 mm), the sound absorbing material with a film of Examples 1 to 11 and Comparative Example 1 A test piece of a sound-absorbing material with a film of ~ 7 is prepared. Next, a double-sided tape is affixed to the back surface of the test piece, and is bonded to the outer peripheral surface of three different types of resin cylinders (φ160 mm, φ120 mm, φ90 mm). Then, after being left at room temperature for 24 hours, it is visually confirmed whether or not there are cracks, blurring, etc. in the film. At this time, when a crack or the like does not occur in the film, it is evaluated as “◯”, and when a crack or the like occurs in the film, it is evaluated as “x”. The evaluation results are shown for each cylinder diameter in the column of “followability” shown in FIGS.

  Further, JIS A is used for the sound absorbing material having no film formed thereon, that is, the urethane foam as the above-mentioned substrate (hereinafter referred to as “sound absorbing material without film”) and the sound absorbing material with a film of Example 1. The sound absorption coefficient was measured based on 1405-2 (normal incidence sound absorption coefficient) (tester: Brüel & Kjær acoustic tester, acoustic tube; 4206 / 4206-T impedance tube basic configuration and transmission loss tube kit). The measurement results are shown in FIG.

  Moreover, elongation (%) was measured based on the method based on JIS K 6400-5 with respect to the simple substance of Examples 1-11 only and the simple substance of Comparative Examples 1-7. The measurement results are shown in the column of “elongation (%)” in FIGS.

  From the above results, it is understood that by forming a film on the surface of the urethane foam, it is possible to suitably absorb sound in a wide frequency range including a low frequency range. Specifically, as shown in FIG. 6, the sound absorbing characteristics of the sound absorbing material with a film of Example 1 are shifted to a low frequency range of about 100 to 400 Hz as compared with the sound absorbing material without a film. The sound absorbing material with a film 1 has a characteristic of suitably absorbing sound in a wide frequency range including a low frequency range, as compared with a sound absorbing material without a film.

  In addition, by using a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group and a polythiol having a thiol group as a raw material for a sound absorbing material film, an enethiol reaction is performed. Utilizing it, a film can be formed simply by irradiating the mixed raw material in which the urethane prepolymer and the polythiol are mixed with ultraviolet rays. This is clear from the sound absorbing material with a film of Comparative Example 6. Specifically, in the sound absorbing material with a film of Comparative Example 6, polythiol was not blended as a raw material, and the raw material containing only the urethane prepolymer was not cured by irradiation with ultraviolet rays, and a film could not be formed. On the other hand, in all the sound absorbing materials with a film of Examples 1 to 11, by adopting urethane prepolymer and polythiol as raw materials, the mixed raw material of prepolymer and polythiol is cured by irradiation with ultraviolet rays, and appropriately A film is formed. From this, it is understood that a film can be formed by irradiation of ultraviolet rays by employing a urethane prepolymer and polythiol as raw materials. Thereby, it becomes possible to manufacture a sound-absorbing material with a film by irradiating ultraviolet rays without performing steps such as a drying step and a heating step, and the manufacturing efficiency is improved. In addition, in the curing reaction using the enethiol reaction, since there is no curing failure due to the presence of oxygen, it is not necessary to block oxygen, and the equipment can be reduced.

  The ratio of the total equivalent number of all thiol groups to the total equivalent number of vinyl ether groups, allyl ether groups and acrylate groups of each urethane prepolymer (ene / thiol ratio) is too high or too low. However, the followability of the film is poor. Specifically, in all the sound absorbing materials with a film of Examples 1 to 11, the ene / thiol ratio is 1.0 to 2.3, and in the evaluation of followability, cylinders of all diameters (φ160 mm, φ120 mm, φ90 mm) and good. On the other hand, in the sound absorbing material with a film of Comparative Example 4, the ene / thiol ratio is 0.5, and in the evaluation of followability, a crack or the like is generated in the film with a cylinder having a short diameter (φ90 mm), and the followability is poor. Moreover, in the sound absorbing material with a film of Comparative Example 5, the ene / thiol ratio is 2.5, and in the evaluation of followability, a crack or the like is generated in the film with a cylinder having a short diameter (φ90 mm), and the followability is poor. Therefore, the ene / thiol ratio is preferably 0.7 to 2.3 in consideration of errors.

  Further, if the average number of functional groups of the polythiol blended as the raw material of the film is too low, the followability is poor. Specifically, in the sound absorbing material with a film of Comparative Example 1, the average functional group number of polythiol is 2.0, and in the evaluation of followability, cracks and the like are formed on the film in cylinders of all diameters (φ160 mm, φ120 mm, φ90 mm). Occurs, and the followability is poor. On the other hand, in all the sound absorbing materials with a film of Examples 1 to 11, the average functional group number of polythiol is 2.5 or more, and in the evaluation of followability, the cylinders of all diameters (φ160 mm, φ120 mm, φ90 mm) are good. is there. From this, it is preferable that the average functional group number of polythiol is 2.5 or more.

  Moreover, the follow-up property of the film is poor whether the weight average molecular weight of the urethane prepolymer blended as the raw material of the film is too high or too low. Specifically, in all the sound absorbing materials with a film of Examples 1 to 11, the weight average molecular weight of the urethane prepolymer is 2755 to 20755, and in the evaluation of followability, cylinders of all diameters (φ160 mm, φ120 mm, φ90 mm). ). On the other hand, in the sound absorbing material with a film of Comparative Example 2, the weight average molecular weight of the urethane prepolymer is 1581, and in the evaluation of followability, cracks and the like are generated in the film in all diameter cylinders (φ160 mm, φ120 mm, φ90 mm), Followability is poor. Further, in the sound absorbing material with a film of Comparative Example 3, the weight average molecular weight of the urethane prepolymer is 30755, and in the evaluation of the followability, a crack or the like occurs in the film with a cylinder having a short diameter (φ90 mm), and the followability is poor. Therefore, the weight average molecular weight of the urethane prepolymer is preferably 2000 to 30000 in consideration of errors.

  Further, when the sound absorbing material is used in the corners and corners, the film is greatly bent together with the base body, so that the elongation of the film is preferably 100% or more. However, when the weight average molecular weight of the urethane prepolymer blended as the film raw material is too low, or when polythiol is not blended as the film raw material, the elongation of the film decreases. Specifically, in the sound absorbing material with a film of Comparative Example 2, the weight average molecular weight of the urethane prepolymer is 1581, and the elongation of the film is 50%. Moreover, in the sound absorbing material with a film of Comparative Example 7, polythiol is not blended, and the elongation of the film is 70%. Also from this, the weight average molecular weight of the urethane prepolymer is preferably 2000 or more in consideration of errors, and it is preferable to blend polythiol as a raw material for the film.

Claims (5)

A substrate made of a synthetic resin porous body;
Using a composition comprising a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group, and an acrylate group as a terminal functional group, and a polythiol having a thiol group, it is formed on at least a part of the surface of the substrate. And a coating
The ratio of the total equivalent number of thiol groups possessed by the polythiol to the total equivalent number of allyl ether groups, vinyl ether groups and acrylate groups possessed by the urethane prepolymer is 0.7 to 2.3. A sound-absorbing material with a coating.   The weight average molecular weight of the said urethane prepolymer is 2000-30000, The sound absorbing material with a film | membrane of Claim 1 characterized by the above-mentioned.   The sound absorbing material with a film according to claim 1 or 2, wherein the average number of functional groups of the polythiol is 2.5 or more.   The sound absorbing material with a coating according to any one of claims 1 to 3, wherein the elongation of the coating (JIS K 6400) is 100% or more. A raw material comprising a urethane prepolymer having at least one of an allyl ether group, a vinyl ether group and an acrylate group as a terminal functional group and a polythiol having a thiol group is applied to at least a part of the surface of the substrate made of a synthetic resin porous body. An attachment process to attach,
A method for producing a sound-absorbing material, comprising: producing a sound-absorbing material with a film by a photopolymerization reaction.

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