JP2007161936A - Polyurethane adhesive vibration damping sheet and production method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a colorless transparent polyurethane adhesive vibration damping sheet having no foam, and a production method thereof. <P>SOLUTION: This polyurethane adhesive vibration damping sheet is obtained by reacting and curing a raw material liquid comprising a polyol, an isocyanate and a catalyst, wherein the polyol is a polypropylene polyol having a molecular mass of 2,000 or more; the isocyanate is at least one of an aliphatic isocyanate and a cycloaliphatic isocyanate; the equivalent ratio (NCO/OH×100) of the isocyanate and the polyol is in the range of 50 to 70; and the average number (F) of functional groups is in the range of 2 to 2.6. In the invention, in addition to or instead of the polypropylene polyol having a molecular mass of 2,000 or more, a polyester polyol having no melting point until -40°C can be also used. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a polyurethane adhesive vibration damping sheet and a method for producing the same.

Conventionally, many polyurethane pressure-sensitive adhesives have been proposed, but few are produced without a solvent.

As a method for producing a polyurethane adhesive without solvent, a method using an aliphatic diisocyanate having 36 C-atoms has been proposed (see Patent Document 1). However, since the 36 C-atom diisocyanate is colored, the polyurethane pressure-sensitive adhesive obtained by this method is unsuitable for applications that are required to be colorless and transparent.

In addition, a segment polyurethane is proposed in which polyethylene glycol is used as a gel-forming dispersion medium and an isocyanate compound is used as a gel-forming skeletal material (see Patent Document 2). However, since this segment polyurethane has polyethylene glycol in the molecule and has a lower molecular weight, it will crystallize at low temperatures and become opaque. In addition, since polyethylene glycol easily absorbs moisture, even if a dehydration treatment is performed before reacting with the isocyanate compound, foaming occurs during the reaction with the isocyanate compound due to subsequent moisture absorption. For this reason, it is difficult to make this segment polyurethane into a transparent sheet material without bubbles.

And the urethane resin adhesive which has the segment chain | strand in the range whose molecular weight of polypropylene glycol is about 200-10000 is proposed (refer patent document 3). However, there is no description or suggestion about the type of isocyanate used in the urethane resin adhesive. Further, there is no description or suggestion that the urethane resin pressure-sensitive adhesive is used for preventing glass breakage, and there is no description or suggestion about means for making a colorless and transparent sheet-like product without bubbles.

Furthermore, a vibration-damping glass and a plastic laminate that prevent both sound and vibration and are useful for windows for vehicles such as automobiles, airplanes, and ships and windows for office buildings have been proposed (see Patent Document 4). The plastic laminate includes an outer hard layer such as glass or plastic and at least one inner layer of a damping plastic material and a flexible plastic material such as polyvinyl butyral. However, although there is a description that polyurethane is preferably used as the vibration damping material, there is no description or suggestion about the composition of the polyurethane.
Japanese Patent Laid-Open No. 50-10828 JP-A-1-304109 JP-A-5-59343 Special Table 2001-506198

The present invention has been made in view of such circumstances, and an object thereof is to provide a colorless and transparent polyurethane adhesive vibration-damping sheet having no bubbles and a method for producing the same.

In order to achieve the above object, the polyurethane pressure-sensitive vibration damping sheet of the present invention is a polyurethane pressure-sensitive vibration damping sheet obtained by reaction curing of a raw material liquid containing a polyol, an isocyanate and a catalyst, A polypropylene polyol having a molecular weight of 2000 or more, the isocyanate is at least one of an aliphatic isocyanate and an alicyclic isocyanate, and an equivalent ratio of the isocyanate to the polyol (NCO / OH × 100) Is a polyurethane pressure-sensitive adhesive sheet in which the average functional group number (F) of the polyol and the isocyanate is in the range of 2 to 2.6.
Here, the average functional group number (F) of the polyol and the isocyanate is defined by the following formula (1).
F = (fp × PB / MWp + fi × IB / MWi) / (PB / MWp + IB / MWi) (1)
fp: Number of functional groups of polyol PB: Number of parts of polyol (parts by mass)
MWp: molecular weight of polyol fi: number of functional groups of isocyanate IB: number of parts of isocyanate (parts by mass)
MWi: Molecular weight of isocyanate

In the polyurethane adhesive vibration-damping sheet of the present invention, a polyester polyol having a melting point of up to −40 ° C. may be used as the polyol in addition to or in place of the polypropylene polyol having a molecular weight of 2000 or more.

In the polyurethane adhesive vibration damping sheet of the present invention, the polyester polyol is preferably an adipic acid ester containing a glycol structure having a side chain.

In the polyurethane adhesive vibration-damping sheet of the present invention, the glycol structure having the side chain includes 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl- Selected from 1,3-propanediol, 1,3-butanediol, 2-ethyl-1,3-hexanediol, 3-methyl-1,3-butanediol, 1,2-propylene glycol and dipropylene glycol One is preferable.

In the polyurethane adhesive vibration damping sheet of the present invention, the polyester polyol is preferably an adipic acid ester having a glycol structure having a side chain and having a primary hydroxyl group at the terminal.

In the polyurethane adhesive vibration damping sheet of the present invention, the C hardness is preferably 40 or less from the viewpoint of the effect of preventing glass breakage. The C hardness is more preferably in the range of 10 to 35. The C hardness can be measured, for example, by the method used in Examples described later.

In the polyurethane adhesive vibration damping sheet of the present invention, the adhesive force is preferably in the range of 0.2 to 5 N / cm at 180 ° peel force. By setting it as this range, it becomes possible to reattach the said polyurethane adhesive vibration damping sheet more easily. The adhesive force is more preferably in the range of 1.5 to 5 N / cm at 180 ° peel force. The said adhesive force can be measured by the method used in the below-mentioned Example, for example.

Moreover, the manufacturing method of the polyurethane adhesive vibration damping sheet of this invention coats the said raw material liquid on the 1st film, and before the said coated material reacts and hardens | cures, the 2nd film is coated on the said coated material. The polyurethane adhesive vibration-damping sheet is produced by reacting and curing the coated material in this state.

In the polyurethane adhesive vibration damping sheet of the present invention, the surface of the first film and the second film may be subjected to a peeling treatment.

In the polyurethane adhesive vibration-damping sheet of the present invention, the polyurethane of any one of the first film and the second film can be obtained by changing the type of surface treatment of the first film and the second film. It is preferable to make the adhesive force with the adhesive vibration-damping sheet weaker than that of the other.

In the present invention, a polypropylene polyol having a molecular weight of 2000 or more is used as a polyol, and at least one of an aliphatic isocyanate and an alicyclic isocyanate is used as an isocyanate. The equivalent ratio of the isocyanate and the polyol and the average number of functional groups By making the above-mentioned range, it is possible to obtain a colorless and transparent polyurethane adhesive vibration-damping sheet without bubbles. In the present invention, in addition to or in place of the polypropylene polyol having a molecular weight of 2000 or more, it is also possible to use a polyester polyol that does not have a melting point of −40 ° C.

Next, the polyurethane adhesive vibration damping sheet of the present invention and the production method thereof will be described in detail.

The polyol used in the present invention is a polypropylene polyol having a molecular weight of 2000 or more. The upper limit of the molecular weight of the polypropylene polyol is preferably 6000. That is, the molecular weight of the polypropylene polyol is preferably in the range of 2000 to 6000. By setting it as the said range, the foaming accompanying the moisture absorption of the polyol at the time of reaction with isocyanate, and coloring of polyol itself can be suppressed. However, the upper limit of the molecular weight of the polypropylene polyol is not limited to this, and it is also possible to use a polypropylene polyol having a molecular weight exceeding 6000. Examples of such polypropylene polyols include low molecular weight glycols, triols, tetraols such as ethylene glycol, propylene glycol, glycerin, trimethylolpropane, pentaerythritol, and the like, which are obtained by addition polymerization of propylene oxide. Can be used. In place of propylene oxide, use of an addition-polymerized ethylene oxide is not preferable because it is hydrophilic and easily absorbs moisture and foams during reaction with isocyanate. Further, when a prepolymer reacted with an isocyanate is used for a part of the polypropylene polyol, foaming at the time of reaction with the isocyanate is further suppressed, and the strength and elongation of the resulting polyurethane adhesive vibration damping sheet are further increased. This is more preferable.

In the present invention, as described above, a polyester polyol having a melting point of up to −40 ° C. may be used as the polyol in addition to or in place of the polypropylene polyol having a molecular weight of 2000 or more. The molecular weight of the polyester polyol is not particularly limited, but is preferably in the range of 1000 to 3000 from the viewpoint of reducing the temperature dependence of physical properties such as adhesive strength and the balance of viscosity. The polyester polyol is preferably an adipic acid ester containing a glycol structure having a side chain. Examples of the glycol structure having a side chain include 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1 , 3-butanediol, 2-ethyl-1,3-hexanediol, 3-methyl-1,3-butanediol, 1,2-propylene glycol, dipropylene glycol and the like.

As the polyester polyol, it is more preferable to use an adipic acid ester having a glycol structure having a side chain and having a terminal primary hydroxyl group. This is because such polyols have high reactivity with isocyanates, and thus can further suppress foaming during the reaction.

The said polyester polyol may be used individually by 1 type, and may use 2 or more types together.

Next, the isocyanate used in the present invention is at least one of an aliphatic isocyanate and an alicyclic isocyanate. By using such an isocyanate, it is possible to suppress coloring of the polyurethane adhesive vibration damping sheet. In addition, as said isocyanate, what does not have a blocking agent is preferable. Examples of such isocyanates include hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), norbornane diisocyanate (NBDI), hydrogenated diphenylmethane diisocyanate (H12MDI), and hydrogenated xylidene diisocyanate. Nart (H6XDI) and the like. These isocyanates are available from, for example, Mitsui Takeda Chemical Company, Nippon Polyurethane Company, Asahi Kasei Chemicals Company, BASF Company, Sumitomo Bayer Company, and the like. As these isocyanates, prepolymers with polyols or those modified as isocyanate dimers or trimers may be used. Moreover, these may be used individually by 1 type and may use 2 or more types together.

The number of functional groups of the polyol used in the present invention is preferably 2 to 3 from the viewpoint of the strength and elongation of the obtained polyurethane pressure-sensitive vibration damping sheet. The number of functional groups of the polyol is more preferably 2.5 to 3 when the number of functional groups of the isocyanate used in the present invention is 2, and when the number of functional groups of the isocyanate is 3. 2 to 2.5 is more preferable.

The equivalent ratio of the isocyanate to the polyol (NCO / OH × 100) is in the range of 50 to 70. By setting it as this range, a suitable adhesive force can be given to the polyurethane adhesive vibration damping sheet obtained.

The average functional group number (F) of the polyol and the isocyanate is in the range of 2 to 2.6. By setting it as this range, the polyurethane adhesive vibration-damping sheet obtained can have appropriate adhesive strength, hardness, strength and elongation. The average functional group number (F) is defined by the following formula (1).

F = (fp × PB / MWp + fi × IB / MWi) / (PB / MWp + IB / MWi) (1)
fp: Number of functional groups of polyol PB: Number of parts of polyol (parts by mass)
MWp: molecular weight of polyol fi: number of functional groups of isocyanate IB: number of parts of isocyanate (parts by mass)
MWi: Molecular weight of isocyanate

For example, when the number of functional groups of the polyol is high, the average number of functional groups (F) is adjusted within the above range by decreasing the number of functional groups of the isocyanate.

Next, examples of the catalyst used in the present invention include tin-based, bismuth-based, lead-based metal catalysts, and amine-based catalysts such as stannous octate and dibutyltin dilaurate. Among the metal catalysts, bismuth-based catalysts such as bismuth octoate and lead-based catalysts such as lead octoate are particularly preferable because foaming during the reaction between the polyol and the isocyanate is further suppressed and the reaction rate is appropriate. Further, as the amine-based catalyst, a relatively hydrophobic catalyst having a long-chain alkyl group is preferable because foaming during the reaction of the polyol and the isocyanate is further suppressed.

A colorless and transparent tackifier may be further added to the polyurethane pressure-sensitive vibration damping sheet of the present invention. Examples of the colorless and transparent tackifier include those having a melting point or softening point of about 100 ° C. of hydrogenated rosin, hydrogenated rosin ester, hydrogenated terpene, styrene, and vinyltoluene. .

In addition to the tackifier, antioxidants, ultraviolet absorbers, ultraviolet stabilizers, hydrolysis stabilizers, softeners, plasticizers, and the like may be added to the polyurethane pressure-sensitive adhesive sheet of the present invention as additives. . In particular, in the polyurethane adhesive vibration-damping sheet using the polypropylene polyol, it is preferable to add an antioxidant, an ultraviolet absorber, and an ultraviolet stabilizer.

The polyurethane adhesive vibration-damping sheet of the present invention can be obtained by applying the raw material liquid containing the above-mentioned various raw materials in a sheet shape and reaction curing.

In the polyurethane adhesive vibration damping sheet of the present invention, the film thickness is preferably 200 μm or more from the viewpoint of the vibration damping effect. The film thickness is more preferably in the range of 0.5 to 1 mm.

The adhesive strength and C hardness of the polyurethane adhesive vibration damping sheet of the present invention are as described above.

Next, the manufacturing method of the polyurethane adhesive vibration damping sheet of the present invention will be described with examples. However, the manufacturing method of the polyurethane adhesive vibration damping sheet of the present invention is not limited to this example.

First, the isocyanate is blended with the polyol dehydrated under reduced pressure. Next, the catalyst is blended in this and stirred and mixed so as not to entrain bubbles. Next, this mixed solution is continuously coated on the first film by a coating device such as a roll coater. Next, the second film is placed on the coated product before the coated product is reactively cured. In this way, by covering the second coated film with the second film, it is possible to prevent dust and dust from being mixed into the coated material, and the thickness of the obtained polyurethane adhesive vibration damping sheet. Accuracy can be improved. In this state, the polyurethane adhesive vibration-damping sheet of the present invention can be obtained by introducing into a curing oven and reaction-curing.

As the first film and the second film, for example, a heat-resistant and rigid resin film such as a polyester film is preferably used. In addition to the polyester film, a polypropylene film, a polymethylpentene film, a polyimide film, a polycarbonate film, and the like can also be used. Those obtained by laminating these films with paper can also be used.

The surface of the first film and the second film may be subjected to a peeling treatment with silicone or an easy adhesion treatment with acrylic urethane. In this case, the adhesive force with the polyurethane pressure-sensitive adhesive sheet of the present invention can be changed by changing the type of surface treatment of the first film and the second film. Here, if the adhesive force with the polyurethane adhesive vibration-damping sheet of one of the first film and the second film is weaker than that of the other, it becomes easier to peel one film, The polyurethane adhesive vibration damping sheet can be easily attached to the glass surface, and is more preferable.

The polyurethane adhesive vibration-damping sheet of the present invention has an effect of preventing damage to glass by sticking to glass, for example. Moreover, the polyurethane pressure-sensitive vibration damping sheet of the present invention is colorless and transparent over a wide temperature range, and is hardly colored over time.

The polyurethane adhesive vibration damping sheet of the present invention can be suitably used, for example, as a protective sheet for glass substrates of liquid crystal display devices and plasma display devices. Liquid crystal display devices and plasma display devices have been made lighter and thinner with the miniaturization or enlargement. However, in the conventional liquid crystal display device and plasma display device, in order to protect the glass substrate constituting the same from the impact, the surface of the glass substrate (the surface opposite to the side on which the liquid crystal display unit is laminated) It was necessary to provide a gap of about 1 to 10 mm between the polarizing film arranged in front of it. By sticking the polyurethane adhesive vibration damping sheet of the present invention on the surface of the glass substrate, it is not necessary to provide the gap, and the thickness can be further reduced. In addition, this makes it possible to further reduce the thickness of the glass substrate. As a result, the liquid crystal display device and the plasma display device can be further reduced in weight and thickness. And, as described above, the polyurethane adhesive vibration damping sheet of the present invention is colorless and transparent without bubbles. Therefore, even when pasted on the glass substrate, how the screen of the liquid crystal display device or the plasma display device is visible (visibility) ) Will not change. Further, since the gap is eliminated, the screen is not distorted even when the polarizing film is pressed with a finger or the like. In this case, since the thickness accuracy is good if the polyurethane adhesive vibration-damping sheet of the present invention produced using the first sheet and the second sheet is attached to the glass substrate, the liquid crystal display device or When the screen of the plasma display device is viewed from any angle, no distortion occurs, and there is no dust or dust in the polyurethane adhesive vibration-damping sheet, so the view is not obstructed.

The polyurethane adhesive vibration-damping sheet of the present invention can be suitably used as a vibration-damping sheet for window glass for houses, window glass for vehicles such as automobiles, aircrafts and ships, and window glass for office buildings. The application is not limited and can be used for various applications.

Next, the polyurethane adhesive vibration damping sheet of the present invention and the production method thereof will be described with reference to examples and comparative examples.

Here, in producing the polyurethane adhesive vibration damping sheet of the present invention, 14 kinds of polyols (hereinafter referred to as polyols A to N) shown in FIG. 1 were used. However, these polyols are merely examples, and the production of the polyurethane pressure-sensitive adhesive sheet of the present invention is not limited to these polyols.

In producing the polyurethane adhesive vibration-damping sheet of the present invention, three kinds of isocyanates (hereinafter referred to as isocyanates AC) shown in FIG. 2 were used. However, these isocyanates are only examples, and the production of the polyurethane adhesive vibration-damping sheet of the present invention is not limited to these isocyanates. In FIG. 2, HDI is hexamethylene diisocyanate, and TDI is tolylene diisocyanate.

And in manufacturing the polyurethane adhesive vibration damping sheet of the present invention, a tin-based catalyst (first tin octoate, hereinafter referred to as catalyst A) was used. However, this catalyst is only an example, and the production of the polyurethane adhesive vibration-damping sheet of the present invention is not limited to this catalyst.

EXAMPLES Next, although an Example and a comparative example demonstrate this invention concretely, this invention is not necessarily limited only to these Examples. In each example and comparative example, “part” and “%” are based on mass. In addition, in the polyurethane adhesive vibration-damping sheet, additives such as tackifiers, antioxidants, ultraviolet absorbers, ultraviolet stabilizers, hydrolysis stabilizers, softeners, plasticizers and the like do not impair the purpose of the present invention. However, it is not particularly limited to these.

Here, first, a method for measuring physical properties of the polyurethane adhesive vibration damping sheet performed in Examples and Comparative Examples will be described.

(appearance)
Appearance was not foamed, and the color difference ΔE * of a polyurethane adhesive vibration-damping sheet that had been allowed to stand at −40 ° C. and 80 ° C. for 1 day was pasted on a white paper to measure the difference from the blank white paper. However, both of them were accepted as 10 or less. For the measurement of the color difference ΔE *, a spectrocolorimeter CM580D manufactured by Minolta was used.

(Long-term productivity)
For long-term productivity, it was determined how many hours of production can be continued from the start of production by using a polyol that has been left in the air for a certain period of time to absorb moisture in the production of a polyurethane pressure-sensitive damping sheet. If it starts to foam when using a polyol that has been allowed to stand in the air for 1 hour or more but less than 2 hours, it will pass (○), and if it is used for a polyol that has been left in the air for 2 hours to absorb moisture, no foaming is observed. Excellent (◎).

(C hardness)
C hardness was measured using a Shore C hardness meter in accordance with JIS K 7312.

(Adhesive force)
The adhesive strength was measured by a 180 ° peel force (N / cm) after a 1 cm width polyurethane adhesive damping sheet was attached to glass in accordance with JIS Z 0237.

(UV stability)
Ultraviolet light stability was measured using a strong energy xenon weather meter SC700-WA manufactured by Suga Test Instruments Co., Ltd. after exposure for 72 hours without water spraying at a black panel temperature of 63 ° C., and then measuring C hardness and color difference ΔE *. . As for the hardness difference, the C hardness change value before exposure was less than 5 (excellent), 5 to less than 10 passed (◯), 10 or more impractical (x). The color difference ΔE * was measured in a state of being pasted on a white paper, and the difference from the blank white paper was within 12 (passed). In addition, since the color difference ΔE * of the polyurethane adhesive vibration-proof sheet adhered to the white paper before exposure was approximately 10, it was determined to pass (◯) if the increase in the color difference ΔE * due to exposure was within approximately 2. It will be. For the measurement of the color difference ΔE *, a spectrocolorimeter CM580D manufactured by Minolta was used. The C hardness was measured using a Shore C hardness meter in accordance with JIS K 7312.

(Glass breakability)
The glass breakability is whether or not the glass breaks by placing an iron plate under a 1.5mm thick glass with a polyurethane adhesive damping sheet and dropping an iron ball of 16Φ from the top from a certain height. Judged by. The case where the glass was not damaged even when dropped from a height of 150 cm was evaluated as ◯, the case where the glass was damaged at a height of 100 to 150 cm was evaluated as Δ, and the case where the glass was damaged at a height of less than 100 cm was rated as x. In addition, in the case of the glass itself which does not stick a polyurethane adhesive damping sheet, it was damaged at a height of 45 cm.

(Comprehensive evaluation)
In the comprehensive evaluation, “◯” indicates that all the above physical property evaluations are acceptable, and “x” indicates that one of the physical properties is unacceptable.

First, 54.63 parts of isocyanate A was blended with 100 parts of polyol A that had been dehydrated for 2 hours under reduced pressure of 1 mmHg (133 Pa) at 80 to 90 ° C. Next, 0.2% of the total amount of catalyst A was blended in this, and the mixture was stirred and mixed with a centrifugal stirrer so as not to cause bubbles. Next, this mixed solution is applied onto a 100 μm-thick silicone-treated releasable polyethylene terephthalate (PET) film using a coating bar so as to have a thickness of 1 mm. A covered PET film was applied. In this state, reaction curing was performed at 100 ° C. for 30 minutes. Thus, the polyurethane adhesive vibration damping sheet of this example was obtained.

A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 1 except that polyol B was used in place of polyol A, and the blending amount of isocyanate A was 91.02 parts.

A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 1 except that polyol C was used in place of polyol A, and the amount of isocyanate A was 136.46 parts.

First, 23.18 parts of isocyanate C was blended with 100 parts of polyol H dehydrated for 2 hours under reduced pressure of 1 mmHg (133 Pa) at 80 to 90 ° C. Next, 0.2% of the total amount of catalyst A was blended in this, and the mixture was stirred and mixed with a centrifugal stirrer so as not to cause bubbles. Next, this mixed solution is applied onto a 100 μm-thick silicone-treated releasable PET film using a coating bar so as to have a thickness of 1 mm, and another releasable PET film is quickly applied thereon. I covered it. In this state, reaction curing was performed at 100 ° C. for 30 minutes. Thus, the polyurethane adhesive vibration damping sheet of this example was obtained.

A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 4 except that polyol I was used instead of polyol H, and the amount of isocyanate C was 11.96 parts.

A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 4 except that polyol J was used in place of polyol H, and the amount of isocyanate C was 11.96 parts.

In the same manner as in Example 4, except that 70 parts of polyol I and 30 parts of polyol K were used instead of 100 parts of polyol H, and the blending amount of isocyanate C was 11.96 parts, a polyurethane adhesive vibration damping sheet Got.

First, 9.79 parts of isocyanate C was added to 100 parts of polyol I dehydrated at 80 to 90 ° C. under a reduced pressure of 1 mmHg (133 Pa) for 2 hours. Next, 0.2% of the total amount of catalyst A was blended in this, and the mixture was stirred and mixed with a centrifugal stirrer so as not to cause bubbles. Next, this mixed solution is coated on a silicone-treated release PET film having a thickness of 100 μm by using a coating bar so as to have a thickness of 1 mm, and another release PET film is quickly covered thereon. It was. In this state, reaction curing was performed at 100 ° C. for 30 minutes. Thus, the polyurethane adhesive vibration damping sheet of this example was obtained.

A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 8 except that the amount of isocyanate C was 11.96 parts.

A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 8 except that the amount of isocyanate C was 13.95 parts.

First, isocyanate C11.94 parts was blended with 50 parts of polyol B and 50 parts of polyol D that had been dehydrated for 2 hours under reduced pressure of 1 mmHg (133 Pa) at 80 to 90 ° C. Next, 0.2% of the total amount of catalyst A was blended in this, and the mixture was stirred and mixed with a centrifugal stirrer so as not to cause bubbles. Next, this mixed solution is coated on a silicone-treated release PET film having a thickness of 100 μm by using a coating bar so as to have a thickness of 1 mm, and another release PET film is quickly covered thereon. It was. In this state, reaction curing was performed at 100 ° C. for 30 minutes. Thus, the polyurethane adhesive vibration damping sheet of this example was obtained.

A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 11 except that 100 parts of polyol D was used instead of 50 parts of polyol B and 50 parts of polyol D.

(Comparative Example 1)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 1 except that polyol E was used in place of polyol A, and the amount of isocyanate A was 273.33 parts.

(Comparative Example 2)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 1 except that polyol F was used in place of polyol A, and the amount of isocyanate A was 390.64 parts.

(Comparative Example 3)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 1 except that polyol G was used in place of polyol A and that the amount of isocyanate A was 1358 parts.

(Comparative Example 4)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 4 except that polyol L was used in place of polyol H, and the amount of isocyanate C was 11.96 parts.

(Comparative Example 5)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 4 except that polyol M was used in place of polyol H, and the amount of isocyanate C was 11.96 parts.

(Comparative Example 6)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 8 except that the amount of isocyanate C was 7.97 parts.

(Comparative Example 7)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 8 except that the amount of isocyanate C was 15.94 parts.

(Comparative Example 8)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 8 except that the amount of isocyanate C was 19.93 parts.

(Comparative Example 9)
A polyurethane adhesive vibration damping sheet was obtained in the same manner as in Example 11 except that 100 parts of polyol B was used instead of 50 parts of polyol B and 50 parts of polyol D.

(Comparative Example 10)
In the same manner as in Example 11, except that 100 parts of polyol N was used instead of 50 parts of polyol B and 50 parts of polyol D, and that the amount of isocyanate C was 8.14 parts, polyurethane was used. An adhesive vibration damping sheet was obtained.

(Comparative Example 11)
Except for using 50 parts of polyol B and 50 parts of polyol D, using 100 parts of polyol A and using 54.63 parts of isocyanate B instead of using 11.94 parts of isocyanate C In the same manner as in Example 11, a polyurethane adhesive vibration damping sheet was obtained.

FIG. 3 shows a summary of various conditions and physical properties of Examples 1 to 3 and Comparative Examples 1 to 3.

As shown in FIG. 3, in Examples 1 to 3 using polypropylene polyols (polyols A to C) having a molecular weight of 2000 or more, the overall evaluation is “good”. On the other hand, in Comparative Examples 1 to 3 using polypropylene polyols (polyols E to G) having a molecular weight of less than 2000, foaming occurred even when the polyol was subjected to dehydration treatment.

FIG. 4 shows a summary of the conditions and physical properties of Examples 4 to 7 and Comparative Examples 4 and 5.

As shown in FIG. 4, in Examples 4 to 7 using polyester polyols (polyols H to K) whose melting points do not exist up to −40 ° C., the overall evaluation is “good”. In particular, in Examples 5 to 7, foaming was not observed even when using a polyol that had been left in the air for 2 hours to absorb moisture, and it was determined that it could withstand long-term production. In contrast, in Comparative Examples 4 and 5 using polyester polyols (polyols L and M) having a melting point near room temperature or higher, the obtained polyurethane adhesive vibration-damping sheet is close to the melting point of the polyester polyol. It crystallized at temperature and became opaque.

FIG. 5 shows a summary of various conditions and physical properties of Examples 8 to 10 and Comparative Examples 6 to 8.

As shown in FIG. 5, in Examples 8 to 10 in which the equivalent ratio of isocyanate to polyol (NCO / OH × 100) is in the range of 50 to 70, the overall evaluation is “good”. On the other hand, in Comparative Example 6 in which the equivalent ratio of isocyanate to polyol (NCO / OH × 100) was 40, it was melted at a high temperature of 80 ° C. and the shape could not be maintained. Moreover, since the hardness was too low, the glass breakability was also poor. Furthermore, in Comparative Examples 7 and 8 in which the equivalent ratio of isocyanate to polyol (NCO / OH × 100) was 80 and 100, the hardness was too high and a decrease in adhesive strength was observed. Moreover, the glass breakability was also poor.

FIG. 6 shows a summary of the conditions and physical properties of Examples 11 and 12 and Comparative Examples 9 to 11.

As shown in FIG. 6, in Examples 11 and 12 in which the average number of functional groups (F) of polyol and isocyanate is in the range of 2 to 2.6, the overall evaluation is “good”. On the other hand, in Comparative Example 9 in which the average functional group number (F) of polyol and isocyanate was 3.0, there was no adhesive force at all. Further, the obtained polyurethane adhesive vibration-damping sheet was low in elongation, and was easily cut and difficult to handle when performing the pasting operation. Furthermore, in Comparative Example 10 using polyol N having a melting point of 50 ° C., it was colorless and transparent at room temperature or higher, but crystallized and became opaque at a temperature lower than that. Furthermore, in Comparative Example 11 using an aromatic isocyanate TDI prepolymer, the appearance after standing for 1 day at 80 ° C. was yellowed, and the UV stability was also poor.

According to the present invention, a colorless and transparent polyurethane pressure-sensitive adhesive sheet without bubbles can be obtained. The polyurethane adhesive vibration damping sheet obtained by the present invention includes, for example, a protective sheet for a glass substrate of a liquid crystal display device or a plasma display device, a window glass for a house, a window glass for a vehicle such as an automobile, an aircraft or a ship. Although it can be suitably used for vibration damping sheets such as window glass for office buildings, its use is not limited and can be used for various purposes.

It is a table | surface which shows the polyol used for the Example and the comparative example. It is a table | surface which shows the isocyanate used for the Example and the comparative example. It is the table | surface which put together various conditions and physical property of Examples 1-3 and Comparative Examples 1-3. It is the table | surface which put together various conditions and physical property of Examples 4-7 and Comparative Examples 4 and 5. FIG. It is the table | surface which put together various conditions and physical property of Examples 8-10 and Comparative Examples 6-8. It is the table | surface which put together various conditions and physical property of Examples 11 and 12 and Comparative Examples 9-11.

Claims (10)

A polyurethane pressure-sensitive adhesive sheet obtained by reaction curing of a raw material liquid containing a polyol, an isocyanate and a catalyst, wherein the polyol is a polypropylene polyol having a molecular weight of 2000 or more, and the isocyanate is an aliphatic isocyanate. At least one of a nate and an alicyclic isocyanate, and an equivalent ratio of the isocyanate to the polyol (NCO / OH × 100) is in a range of 50 to 70, and the polyol and the isocyanate A polyurethane adhesive vibration damping sheet having an average functional group number (F) in the range of 2 to 2.6.
Here, the average functional group number (F) of the polyol and the isocyanate is defined by the following formula (1).
F = (fp × PB / MWp + fi × IB / MWi) / (PB / MWp + IB / MWi) (1)
fp: Number of functional groups of polyol PB: Number of parts of polyol (parts by mass)
MWp: molecular weight of polyol fi: number of functional groups of isocyanate IB: number of parts of isocyanate (parts by mass)
MWi: Molecular weight of isocyanate The polyurethane adhesive vibration-damping sheet according to claim 1, wherein a polyester polyol having a melting point of up to -40 ° C is used as the polyol in addition to or in place of the polypropylene polyol having a molecular weight of 2000 or more. The polyurethane adhesive vibration-damping sheet according to claim 2, wherein the polyester polyol is an adipic acid ester containing a glycol structure having a side chain. The glycol structure having the side chain is 3-methyl-1,5-pentanediol, 2-methyl-1,3-propanediol, 2-butyl-2-ethyl-1,3-propanediol, 1,3- The polyurethane according to claim 3, which is one selected from butanediol, 2-ethyl-1,3-hexanediol, 3-methyl-1,3-butanediol, 1,2-propylene glycol and dipropylene glycol. Adhesive damping sheet. The polyurethane pressure-sensitive adhesive vibration sheet according to claim 2, wherein the polyester polyol is an adipic acid ester having a glycol structure having a side chain and a terminal hydroxyl group. C polyurethane hardness is 40 or less, The polyurethane adhesive vibration damping sheet as described in any one of Claim 1 to 5. The polyurethane adhesive vibration-damping sheet according to any one of claims 1 to 6, wherein the adhesive strength is in the range of 0.2 to 5 N / cm at 180 ° peel force. It is a manufacturing method of the polyurethane adhesive vibration-damping sheet as described in any one of Claim 1 to 7, Comprising: Before coating the said raw material liquid on a 1st film and the said coated material reacts and cures, A method for producing a polyurethane adhesive vibration damping sheet, wherein the film of No. 2 is placed on the coated product, and the coated product is reaction-cured in this state. The manufacturing method of the polyurethane adhesive vibration damping sheet of Claim 8 which performs a peeling process on the surface of a said 1st film and a said 2nd film. By changing the type of surface treatment of the first film and the second film, the adhesive force with the polyurethane adhesive vibration damping sheet of either the first film or the second film is changed to the other The method for producing a polyurethane adhesive vibration-damping sheet according to claim 9, wherein the polyurethane adhesive vibration-damping sheet is made weaker than that.

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