JPS61275351A - Urethane resin composition for sheet - Google Patents

Abstract

PURPOSE:To provide the title compsn. which has excellent weather resistance and gives moldings which causes neither reduction in thickness and surface smoothness, nor discoloration, blooming and whitening and is non-tack, consisting of urethane resin, an ultraviolet absorber and a deterioration inhibitor. CONSTITUTION:An aliph. isocyanate contg. no unsaturated bond other than the isocyanate group is reacted with a polyester polyol to obtain a urethane resin (A) having a weight-average MW (Mw) of 70,000-200,000. 20d-80wt% ultraviolet absorber (B) having an MW of 350 or above, represented by formula I [wherein R1, R2 are each a straight-chain or branched (cyclo) alkyl, aryl, aralkyl] and 80-20wt% deterioration inhibitor (C) having an Mw of 1,700 or above and contg. a structural unit having a repeating unit of formula II (wherein R is a 2-10C alkylene; R1 is H, a1-10C alkyl; R2 is a 1-10C alkyl; R3, R4 are each H, methyl) are blended with 100pts.wt. component A in such a proportion that the combined quantity W in pts.wt. of components B and C has a value at least equal to the one calculated from formula III (wherein t is a thickness in mu of a sheet).

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a specific urethane resin composition for sheets that has been modified with a specific modifier. Due to the excellent weather resistance exhibited by the composition, even when exposed outdoors, the predetermined thickness and surface smoothness of the sheet are maintained, and the sheet maintains a high level of surface smoothness without discoloration, blooming, whitening, adhesion, etc. This invention relates to a urethane resin composition for sheets that provides quality sheets.

More specifically, urethane grease-resistant A having a specific chemical composition
A 7-piece urethane resin composition containing a specific ultraviolet absorber B component and a deterioration inhibitor C component as modifiers corresponding to the desired sheet thickness (unit: μ). Products: The urethane resin composition for sheets can be used to produce coating materials, coating materials, laminated materials, synthetic leather, fibers, etc. by various molding methods such as extrusion, calendaring, casting, and lamination. The present invention relates to a urethane resin composition for sheets, which particularly exhibits the ability to prevent the thickness of 7-sheets from decreasing when molded into 7-sheets for applications such as 7-sheets, etc., due to significantly superior weather resistance not previously available.

[Conventional technology]

Conventionally, urethane resin sheets have excellent mechanical performance such as impact resistance and abrasion resistance, and chemical resistance against water, oil, etc.
It is used in a wide range of applications such as building materials and automobile parts. However, the sheet generally has poor weather resistance, so
Particularly when used outdoors, it is necessary to take measures such as adding pigments to give the product a deep color, and there are significant restrictions when using it as it is.

For example, if you use it in a transparent state as is.

Discoloration occurs in a short period of time (for example, within one year when used outdoors), the surface of the sheet becomes sticky, or unpleasant changes such as pluming or whitening of the urethane resin component occur.Especially incyanate. Urethane resins whose main components are aliphatic incyanates, such as hexamethylene diisocyanate and 4゜4-dicyclohexylmethane diisocyanate, which have no unsaturated bonds other than groups, and polyester-type polyols, such as adipic acid-based polyester polyols. (Hereinafter, it may be abbreviated as component A resin.) Sheets formed from the resin (hereinafter sometimes abbreviated as component A resin) have a fatal drawback, which is that they suffer from a significant thickness reduction that is characteristic of long-term outdoor exposure.

Conventionally, many methods have been proposed for improving the weather resistance of urethane resins, which have the above-mentioned drawbacks, by adding specific stabilizers, etc. However, none of them are yet satisfactory from a practical standpoint. .

For example, in Japanese Patent Publication No. 56-17386, "Production method of polyurethane sheet with improved properties", specifically, 2
-(2-hydroxy-5-methyl-phenyl)benzotriazole [Tinuvin P (manufactured by Ciba Geigy)] and 2-
At least one compound represented by formula (1) such as (2-hydroxy-3-57-diitzamylulfenyl)benzotriazole [Tinuvin 328 (manufactured by Ciba Geigy)] and 4-benzoyloxy-2,2 A polyurethane resin solution containing at least one compound represented by formula (2) such as , 6,6-tetramethylpiperidine [Sanol LS744 (manufactured by E-Kyodo Co., Ltd.]) is applied onto a substrate, and then a solvent for the solution is applied. A method for producing a polyurethane sheet with excellent light resistance and gas coloring resistance has been proposed, which is characterized by coagulating the polyurethane sheet in a solvent solution which is compatible with the polyurethane resin but is not compatible with the polyurethane resin.

However, in the above proposal, the total blending amount of the compound of formula (1) and the compound of formula (2) for 100 parts of polyurethane oil was adjusted to a relatively large amount (for example, the film thickness 2
Even if the amount is 3.5 parts by weight (00μ), the effect of preventing thickness reduction is insufficient, and this phenomenon is particularly noticeable in the above-mentioned A component resin. In this case, it also shows a tendency to whiten. On the other hand, a small amount (for example, 0.5 weight i° with a film thickness of 500μ)
Part) does not provide the expected excellent weather resistance to prevent discoloration, discoloration, thickness reduction, etc.

Furthermore, in JP-A-60-17180, "Sheet-like material" refers to a sheet-like material in which a Ho81 structure is impregnated and/or coated with polyurethane, and the polyurethane contains a compound represented by the following general formula. A sheet-like material is proposed, which is characterized by containing.

The above proposal proposes that when dyeing artificial leather consisting of a fiber structure and polyurethane, polyurethane/polyurethane in the artificial leather before dyeing is used.
To provide artificial leather and other 7-t-like materials that prevent the deterioration of polyurethane and hardly cause color listing or color ending, since the deterioration of polyurethane deteriorates during storage and the deterioration has a negative effect on dyeability. It is not intended for use as an outdoor sheet material that requires excellent weather resistance.

As shown in the comparative example described later,
Only the compound represented by the general formula disclosed in No. 80,
This is only to the extent of preventing polyurethane from deteriorating during storage, but cannot practically prevent thickness reduction, discoloration, discoloration, etc. when used outdoors. , weather resistance for at least two years when used outdoors) was strongly desired.

[Problem that the invention seeks to solve]

The present inventors have conducted extensive research into improving the RLT weatherability of urethane resins, which has been desired in the past.

As a result, it has been found that in sheets molded from conventional molding urethane resin compositions that use component A resin, there is a significant problem of thickness reduction due to poor weather resistance.

The inventors of the present invention aimed to provide a sheet with a high degree of weather resistance (for example, about 3 years of outdoor use) without interfering with the excellent mechanical performance and chemical resistance that urethane resin has. In particular, we continued our research on component A resin.

As a result, for the A component resin; an ultraviolet absorber B component (hereinafter referred to as
It is sometimes abbreviated as component B. ), a deterioration inhibitor component C (hereinafter abbreviated as component C), a deterioration inhibitor with a specific structure that is more than a specific weight average molecular weight (hereinafter sometimes abbreviated as Mw) and contains a triazine group and a piperidine group. A urethane resin composition for a sheet that satisfies the following conditions: the total weight parts of the B component and the C component are not less than the specified amount. We have made the unexpected discovery that when using the B component and the C component, they act synergistically on the A component resin, which can solve all the problems of the A component resin mentioned above at once, and we have completed the present invention. Ta.

That is, the present invention exhibits a high degree of weather resistance, maintains the initial predetermined thickness and surface smoothness of the sheet molded product even after long-term outdoor exposure, and prevents discoloration, blooming, whitening, and Gives high quality sheets without the occurrence of stickiness,
The present invention provides a composition of urethane resin for sheets, which includes an aliphatic incyanate having no unsaturated bonds other than incyanate groups and a polyester star polyol.

The term "sheet" used in the present invention refers to a planar molded product that is extremely thin compared to its length and width, and is used to include films that generally have a thickness of 200 μm or less.

The above objects and other objects and advantages of the present invention will become apparent from the following description.

[Means for solving problems]

The present invention uses the following urethane resin A component (100 liters by weight)
i′! In contrast, when the ratio of parts by weight of the ultraviolet absorber B component and the anti-degradation agent C component is 20:80 to 80:20, and the thickness μ) is The total weight part W with the C component is expressed by the following formula: -o, oo*s t W = 0.4 5 + 211e --
- A urethane resin composition for a sheet, characterized in that it contains at least the total weight part calculated by CI: 1.

A. A urethane resin whose main components are an aliphatic incyanate and a polyester polyol, which have no unsaturated bonds other than isocyanate groups.

An ultraviolet absorber having a molecular weight of 350 or more and represented by the following general formula:

ct (in the formula; RI or R, may be the same or different; each has 2 to 12 carbon atoms, an optionally branched alkyl group, cycloalkyl group, aryl group, or aralkyl group: c, m A deterioration inhibitor containing a structural unit represented by the following general formula in the repeating unit and having a weight average molecular fi:l of 700 or more.

......... (Alkyl group having 1 to 10 carbon atoms; R1 or R1 may be the same or different and each represents a hydrogen atom or a methyl group.) Thickness of a sheet molded from the urethane resin composition for sheets of the present invention From the viewpoint of practical mechanical strength, etc.
．． 1! ~2000μ is preferred, and 50μ ~ 1500μ is more preferred.

The aliphatic incyanate having no unsaturated bond other than the incyanate group, which is the raw material compound of the A component resin used in the present invention, is P-7 ethylene diisocyanate; 4.
4-diphenylmethane diynecyanate), 2.4-)ylene diisoquanate, 2.6-tolylene diyne 7
So-called aromatic long inocyanates such as anate, chlorinated inocyanate, triinocyanate, naphthalene 1,5-diisocyanate; lysine diisocyanate,
This excludes so-called aliphatic in7anates having an unsaturated bond such as a double bond in addition to an isocyanate group such as diethyl fumarate diincyanate. Examples of aliphatic isocyanates having no unsaturated bond other than the incanate group include pentamethylene diinocyanate, hexamethylene diinocyanate, heptamethylene diinocyanate), 4,4-synchrohexylmethane diisocyanate, and 4,4-dicyclohexyl. Examples include dimethylmethane diisocyanate, water-added 2,4-toluylene diincyanate, water-added 2,6-toluylene diincyanate, and among these, hexamethylene diisocyanate and 4,4-dicyclohexylmethane. Diisocyanate is good.

Polyester-type polyols, which are other raw material compounds for the A-component resin used in the present invention, are: dicarboxylic acid condensed with an excess of polyol component to have a hydroxyl group at the end, polycarbonate ester having a hydroxyl group at the end, It includes polymerized lactone glycol esters and those condensed with mustard oil; the dicarboxylic acids mentioned here include succinic acid, geltaric acid, adipine acid, pimelic acid, speric acid, azelaic acid, and separaic acid. Polyols include saturated fatty acids such as maleic acid, unsaturated acids such as fumaric acid, aromatic acids such as phthalic acid and ylental acid, and dimer acids. Diols such as butylene glycol and hexamethylene glycol, glycerin, trimethylolpropane, 1.2.
Refers to triols such as 6-hexanetriol and trimethylolethane, and hexaols such as betaerythritol and sorbitol; polycarbonate esters having a hydroxyl group at the end include diethyl Carbonate esters such as carbonate, dipropyl carbonate, phenyl carbonate,
It refers to a product obtained by transesterifying polyold as described above.

Among these: adipic acid, sepatic acid, i-leic acid, dimeric dicarboxylic acids; polyols of ethylene glycol, diethylene glycol, propylene glycol, butylene glycol, trimethylolpropane; and/or polycarbonate esters having a hydroxyl group at the end:
Polyester-type polyols are recommended. These polyester-rich polyols can be produced by known methods. For example, in the case of adipic acid-based polyester polyols, a known method is used in which 1 mol of adipic acid, 1 mol of diethylene glycol, and 0.06 mol of trimethylolpropane are reacted. The following methods can be mentioned.

In the present invention, the main component in a urethane resin whose main components are an aliphatic incyanate having no unsaturated bonds other than the incyanate group and a polyester type polyol is a main component having an unsaturated bond other than the incyanate group. This means that the molar weight of the aliphatic incyanate and the polyester type polyol is 80 molar weight or more, and such component A resin is, for example, an aliphatic incyanate having no unsaturated bond other than the above-mentioned incyanate group. An example is one obtained by a known addition/condensation crosslinking reaction in a ratio of 4 mol, polyester-coated polyol 0.5 mol, and chain extender (for example, butylene glycol) 0.1 mol.

In addition, the weight average molecular t (MW) of the above-mentioned component resin is preferably 70,000 to 200,000 because it can easily exhibit excellent performance, and 70,000 to 150,000.
It is more preferable.

The ultraviolet absorber component B represented by the general formula [■]° used in the present invention' needs to have a molecular weight of 350 or more. Those with a molecular weight of less than 350, such as 2-(2-1=droxy-5'-methyl-phenyl)penztriazole (for example, trade name Tinuvin P: Molecule i 225), have poor weather resistance as in the comparative example described later. It has poor properties and causes surface adhesion, blooming, etc. It is also said to improve weather resistance, for example, 2- (2'-?
-)'oxy3-5'-t-butyl-phenyl)
-5-chloroben/) IJ azole (for example, trade name Tinuvin 327; molecular weight 357.51) lacks affinity with the A component resin used in the present invention, and in addition to problems with weather resistance, the ultraviolet absorber Sheets that contain this have the disadvantage that they are colored from the beginning.

In the above general formula [■], the molecular weight satisfies the condition of 350 or more, R8 or R2 may be the same or different, and each has a branched chain and has 2 to 12 carbon atoms. It represents an alkyl group, a fuchloroalkyl group, an aralkyl group, or an aralkyl group, which may have a substituent such as a methyl group or a butyl group. It doesn't matter if it's something. Examples of these groups include ethyl group, butyl group (n, s +, 1-11-), amyl group (n-1i-1, t-1, etc.), hexyl group (n-1, etc.)
Alkyl groups such as octyl group (1-, etc.), nonyl group, dodecyl group; 7-chloroalkyl group such as cyclopropyl group, cyclohexyl group; Group; benzyl group, methylbenzyl group, phenethyl group, 7enylprobyl group,
Examples of aralkyl groups such as 2-phenylglobyl group include 2-(2-
Hydroxy-3-5'-di2'-7enylprobyl-7enyl)benzotriazole [trade name, Tinuvin 23
4; molecular weight 447], 2-(2-hydroxy-3-5'
-di-t-amyl-phenyl)be/citriazole [trade name, Tinuvin 328; molecular weight 351], and these UV absorbers are easily available;
It can be used particularly preferably. Moreover, if desired, there is no problem in using two or more of these ultraviolet M absorbent B components in combination.

The deterioration inhibitor component C used in the present invention, which contains the structural unit represented by the general formula (1) in its repeating unit, must have an Mw of 1700 or more. Mv
Non-grooved sheets with an r of 1700 are undesirable because they tend to cause specific problems such as sheet deterioration, which causes the surface to lose its smoothness and become rough, and the thickness of the sheet to become thinner. Preferably, sheets with a molecular weight of 2300 or more are used. Good.

・・・・・・・・・・・・-CII [) The above formula [in the town, the molecular weight satisfies the condition of 1700 or more; R is an ethylene group, a butylene group, a pentamethylene group, group, an alkylene group having 2 to 10 carbon atoms such as a hexamethylene group, an octamethylene group, a decamethylene group: R2 is a hydrogen atom, a methyl group, a gummy group,
An optionally branched alkyl group having 1 to 10 carbon atoms such as amyl group, heptyl group, octyl group, and dobufur group; R2 is an optionally branched alkyl group having 1 to 1 o carbon atoms; Group; Rs't or R6 may be the same or different and each represents a hydrogen atom or a methyl group.

As the deterioration inhibitor Cff containing the structural unit represented by the above-mentioned general formula 1 used in the present invention in the repeating unit, in particular, only this structural unit is used as a repeating unit (usually, the number of repeating units is 20 or less). ), R is a hexamethylene group, R7 is a hydrogen atom, and R8 has 4 to 4 carbon atoms.
An alkyl group which may have 8 branched chains, R8 and R1 are hydrogen atoms, and a molecular weight of 1,700 or more is preferable, such as the product name 5ANOL.
LS 944 LD C (manufactured by Sankyowa) l:2,4-dichloro0-6-(1,1,3,3-tetramethylbutylamino)-1,3,5-triazine/N,N-bis(2゜2
, 6.6-tetramethyl-4-piperidyl)xamethylenediamine polycondensate].

In order for the urethane oil composition for sheets of the present invention to provide the sheet molded products with the above-mentioned excellent performances, it is necessary to
0 valuable parts, ultraviolet absorber B component and deterioration inhibitor C
The weight ratio of 31% to the ingredients is 20:80 to 80:20,
In addition, when the thickness of the sheet is μ), the total weight part W of the B component and the C component is expressed by the following formula: −O,0LISI t W= 0.45 + 2・e −=・CI) It is necessary to add more than the total weight part calculated by .

In the above CI) formula, the sheet thickness t is 50 μ, 10
0μ, 200μ and 500. To specifically show the case of g, the total weight part W is 1.97.1.6.1.11, respectively.
and 0.57. Therefore, the ratio of parts by weight of the ultraviolet absorber B component and the deterioration inhibitor C component is 20:80 to 80.
:20, and if these conditions are not met, it becomes difficult to obtain a 7-tate having a high degree of weather resistance, which is not preferable.

A 7-piece urethane resin composition that exhibits excellent performance can be obtained by blending in a slightly excess amount of the total weight part W calculated by the formula CI), and there is no particular restriction on the number of parts by weight that is blended in excess. do not have. However, it is usually preferable for the weight part to be added in excess to be about 60 parts or less of the calculated total weight part W, and the purpose of the present invention can be sufficiently achieved by adding the excess amount. can do.

The urethane tM resin composition for sheets of the present invention can be prepared by adding the B component and the C component to the A component resin in the production process, or adding the B component and the C component to the A component resin.
It can also be made using mixing means such as a mold blender, Banbury mixer, Hempfel mixer, tumbler mixer, etc.

The urethane resin composition for sheets of the present invention may optionally contain other additives, such as antioxidants, lubricants, pigments,
Fillers, flame retardants, polishing agents, etc. can be used.

Examples of the antioxidant that can be added to the urethane resin composition for sheets of the present invention include 2,2-methylene-bis-(4
-methyl-6-t-butylphenol), triethylene glycol-bis-3-(3-t-butyl-4-hydroxy-5-methyl-phenyl)propionate, l,
3.5-trityl-2,4,6-tris(3,5-di-
t-butyl-4-hydroxy-7benzyl) ink/tetrakis/methylene-3-(3,5-di-t-butyl-4
'-hydroxyphenyl)probionate/methane, etc.

Examples of lubricants that can be blended include waxes such as montanic acid ester wax (manufactured by Hoechst Co., Ltd., trade name Hoechst Wax); fatty acid amides such as ox7 stearamide and oleic acid amide; polyethylene wax; can be mentioned.

〔Effect of the invention〕

The urethane resin composition for sheets of the present invention can be molded by various molding methods, and when molded into a sheet molded product such as a coating material, a covering material, a laminated material, a heat insulating material, etc., the above-mentioned B component and C The components act synergistically on the A-component resin, exhibiting a high level of weather resistance that has not been achieved with conventional urethane resin compositions for sheets, especially suitable for outdoor use, and reducing thickness.

It exhibits a remarkable effect of inhibiting discoloration/discoloration, blooming, whitening, adhesion, etc., and maintains surface smoothness, so its industrial significance is extremely large.

The present invention will be further explained below with reference to Reference Examples, Examples, and Comparative Examples; however, the present invention is not limited to the following Examples.

In addition, as a weather resistance test, the fifth accelerated deterioration test and weather
A meter test was conducted.

(1) Accelerated deterioration test method (hereinafter sometimes abbreviated as QUV test) A sheet formed from a urethane resin composition was tested using a feather meter manufactured by Q Panel Company, with a lamp lighting time of 8 hours and a temperature An accelerated deterioration test was conducted under the conditions of 70°C, lights out, dew condensation time for 4 hours, and temperature of 50°C.

(11) Weather meter test method (hereinafter referred to as WOM
It is sometimes abbreviated as "test". ) The same sheet used for the QUV test was used as a sample, and a Sunshine Weathermeter manufactured by Suga Test Instruments Manufacturing @3 was used.
Except for water spraying for 18 minutes out of 120 minutes, JIS
A weather meter trial run was conducted in accordance with the DO205 test method.

Using the above two test methods, durability of about 1000 hours or more is required to determine that the product can be used outdoors and is practical. During the weather resistance test, the soap samples were periodically observed with the naked eye to check for decrease in sample thickness, coloration, blooming, surface smoothness, etc.
Whitening and stickiness were investigated and evaluated by grading ○ when no change was observed in the sample, Δ when a slight change was observed, and X when a clear change was observed.

[Creation of urethane (support) fat]

Reference Example 1 985 parts by weight of polyester polyol obtained by reacting 1,4-butanediol and adipic acid as main components,
! :, 340 parts by weight of 4,4-cyclohexylmethane diisoquanate and 90 parts by weight of 1,4-butanediol as a chain extender were reacted to prepare a urethane resin having an Mw of about 94,000.

Reference Examples 2 to 3゜A total of 1090 parts by weight of the adipic acid polyester type polyol and the chain extender 1,4-butanediol was used in the same manner as in Reference Example 1, and as an incyanate compound,
In Reference Example 2, 225 parts by weight of hexamethylene diinphanate was reacted, and in Reference Example 3, 335 parts by weight of 4,4-diphenylmethane diinphanate were reacted, and in Reference Example 2, Mw
About 74,000, My about 112,000 in reference example 3
I created each of them.

Examples 1-7 and Comparative Examples 1-7゜Urethane tI! As the It fat A component, the one with a specific weight average molecular weight prepared in Reference Examples 1 and 3 was used.
The product name Tinuvin 234 [:2] is used as the ultraviolet absorber B component.
-(2-hydroxy-3,5-di-2'-phenylpropyl-phenyl)penztriazole], trade name Tinuvin 328 [2-(2'-hydroxy-3.5-sheett)
-amyl-phenyl)benzotriazole], trade name Tinuvin Pt: 2-(2'-hydroxy-5-methyl-7enyl)benzo) + J azole], and as the deterioration inhibitor C component, the general formula [ It has a decoy structural unit,
Rt, Rt, Rs chi deviations are also H atoms, R car (CHρ
.

-1R1 is a 1.1.3.3-tetra-methyl-butyl group and the weight average molecular weight is approximately 2360 using the trade name Tenor LS944LD, and the amount shown in Table 1 is calculated based on 100 parts by weight of the urethane resin component. A urethane resin composition for a sheet having a total number of parts by weight of component B and a proportion of parts by weight of component B and component C was prepared using a V-type breaker/turret.

Next, in order to conduct a weather resistance test on the composition shown in Table 21, the V resin composition was heated on a press plate at 140°C.
, 5 molecule heat; then apply pressure of 30 kf/cII several times to remove air; finally, process at 30 kf/cd, 155°C for 10 minutes, cool and mold) to a 7-t thickness t shown in Table 21. , using the thus obtained sheet as a sample,
The QUV test and WOM test described above were conducted. The results of this weather resistance test are shown in Table 22.

In addition, as Comparative Example 8, a urethane resin composition was prepared in which 1.2 parts by weight of Tinuvin 234, which is the B component, was blended alone without blending Tenor LS 944 LI), which was the C component in Example 1; as Comparative Example 9, A urethane resin composition was prepared in which 1.2 parts by weight of Tenor LS 944 LD, which is a component C, was not blended with Tinuvin 234, which is the B component in Example 1, and the sheet thickness was 208μ and 201μ. It was molded into a material and tested for weather resistance.
There is no mutual effect on weather resistance, and the various performances are similar to the test results of Comparative Examples 4 and 5 in Table 2 (1), so it cannot be used practically as a urethane resin composition for outdoor sheet molded products. It was not possible.

As can be seen from the weather resistance test results shown in Table 2, Example 1 was molded from the urethane resin composition for sheets of the present invention.
All of the sheets No. 7 to 7 show outstanding weather resistance performance that cannot be achieved with conventional urethane resin compositions, and have a rating of 30
In the weather resistance test after 00 hours, the sheet was an excellent sheet with no decrease in thickness observed at all.

On the other hand, the urethane resin for sheets of the present invention m5! The various performances of the sheets using the urethane resin compositions shown in Comparative Examples 1 to 7 that do not meet the requirements of Examples 1 to 7 are as shown in Table 2.
The performance is significantly inferior to that of 7, and it is absolutely
It was not practical for outdoor use.

Example 8: 100 parts by weight of the urethane resin prepared in Reference Example 2, and 0.8 parts by weight of Tinubi/234 (trade name) as the ultraviolet absorber B component.
Product name Sanol L as part by weight and deterioration inhibitor C component
After weighing 0.4 parts by weight of S 944 LD and dissolving it in 380 parts by weight of chloroform with vigorous stirring, the solution was cast onto release paper to form a sheet with a dry thickness of 197 μm at about 25°C.

QUV test and WO test were conducted on the 7-t in the same manner as in Example 1.
I did MK@. As a result, 3000 in the QUV test
There was no change in thickness over time, and no changes such as coloring or whitening were observed.

On the other hand, the WOM test was also good up to 2,700 hours, but after 3,000 hours, although no decrease in thickness was observed, the surface smoothness was slightly inferior and blooming was observed.

Example 9 500 parts by weight of a polyester type polyol obtained by reacting 1,4-butanediol and adipic acid as main components was reacted with 300 parts by weight of 4,4-dicyclohexyl 7/l/)tan diisocyanate. For the obtained prepolymer, 100% of 1,4-butanediol, 16% of Tinuvin 234 (trade name), and 16% of Sanol LS (trade name) were added.
A liquid urethane resin composition having a weight average molecular weight of 113,000 was prepared by adding 62 parts by weight of a solution for preparing v4 at a weight ratio of 4 Ll) to 8:1.

In this composition, the ultraviolet absorber component B was 0.93 parts by weight and the deterioration inhibitor C component was 0.47 parts by weight based on 100 parts by weight of the urethane resin.

Immediately after the reaction, the resin liquid was cast onto release paper. Then, using the same press plate method as described above, it was molded into a sheet with a thickness of 202 μm. ``The sheet was subjected to a QUV test and a WOM test using the same method as the weather resistance test described above.

As a result, even after 3,000 hours had passed, there was no change in the various properties listed in Table 2, such as decrease in thickness, coloring, and whitening, and the sheet was extremely excellent.

Claims (1)

[Scope of Claims] 1) The ratio of ultraviolet absorber B component and deterioration inhibitor C component to 100 parts by weight of urethane resin component A is 20:80 to 80:20, and , when the thickness (μ) of the sheet is, the total weight part W of the B component and the C component is expressed by the following formula, W=0.45+2・e−^0^. ＾0
A urethane resin composition for a sheet, characterized in that it contains at least the total weight part calculated by ^0^5^5t...[I]. A. A urethane resin whose main components are an aliphatic isocyanate and a polyester polyol, which have no unsaturated bonds other than isocyanate groups. B, an ultraviolet absorber having a molecular weight of 350 or more and represented by the following general formula. ▲There are mathematical formulas, chemical formulas, tables, etc.▼…………[II] (In the formula: R_1 or R_2 may be the same or different; each has 2 to 12 carbon atoms, even if it has a branched chain. (Represents a good alkyl group, cycloalkyl group, aryl group, or aralkyl group.) C. A deterioration inhibitor having a weight average molecular weight of 1,700 or more and containing a structural unit represented by the following general formula in the repeating unit. ▲There are mathematical formulas, chemical formulas, tables, etc.▼…………[III] (In the formula; R is an alkylene group having 2 to 10 carbon atoms: R_
1 is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms:
R_2 is an alkyl group having 1 to 10 carbon atoms; R_3 or R_4 may be the same or different and each represents a hydrogen atom or a methyl group; )