JP3405097B2 - Anti-fog resin sheet - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an antifogging resin sheet. More specifically, it is a sheet having a surface that prevents fogging on the surface due to condensation of water vapor, and in particular, it is heated by an indirect heating method and does not reduce the antifogging property even after being formed into various shapes, for example, a container shape. Regarding a resin sheet.

[0002]

2. Description of the Related Art Conventionally, transparent resin sheets such as styrene resin sheets, polyester resin sheets, polypropylene resin sheets and vinyl chloride resin sheets have been widely used as packaging materials and lid materials for various foods. . These transparent resin sheets have excellent transparency, water resistance, and excellent moldability, but their surface is extremely hydrophobic, so water (steam) that condenses in response to changes in temperature and humidity.
Often do not wet the surface uniformly, but become fine water droplets and stop on the surface, and this adheres to the entire surface, so-called clouding often occurs. The occurrence of cloudiness not only reduces the commercial value of various containers that are characterized by transparency, but also non-uniformly agglomerated and adhered moisture affects the food stored in the containers, and In some cases, it caused problems such as deterioration and corruption.

Therefore, in order to prevent water drops from adhering to the surface of various plastic sheets or films,
A method of blending various antifogging agents and coating on the surface of a sheet or film has been proposed, and some of them have been put into practical use. For example, as a method of adding various antifogging agents to a resin to form an antifogging sheet, (1) a method of kneading a polyglycerin fatty acid ester into a vinyl chloride resin (see JP-A-54-56647) (2) ) Method of kneading polyglycerin fatty acid ester into polyolefin film (see JP-A-4-334449) (3) Polyhydric alcohol, ester of hydroxystearic acid, polyhydric alcohol and fatty acid ester antifog agent are polyolefin resin And the like (see Japanese Patent Application Laid-Open No. 6-93139). However, when an antifogging agent is kneaded into these resins, there are problems that the antifogging agent floats up on the surface of the sheet, the transparency of the sheet is extremely lowered, and the sheet surface becomes sticky and blocking occurs.

On the other hand, as a method of compensating for these drawbacks, a method of coating various antifogging agents on the surface of the sheet has been proposed. For example, sucrose fatty acid ester is added to (4) styrene-based resin sheet in an amount of 0.1 to 0.1 part by weight of a surfactant.
A method of applying a liquid mixed with 10 parts by weight (Japanese Patent Publication No. 59-59).
No. 19584) (5) A method of allowing a sucrose fatty acid ester to be present in a polyolefin-based film or sheet (see JP-A-54-99180). However, even in a sheet coated with these sucrose fatty acid esters on the surface, after heating the sheet by the indirect heating method,
There is a defect that the antifogging property is lost when a molded product is manufactured.

Furthermore, in order to make the best use of the transparency, a polyester resin sheet having an extremely good transparency used as a container is heat-molded by an indirect heating method capable of maintaining the transparency of a molded product as compared with the direct heating method. The method is adopted. Therefore, in the case of a molded product of a polyester-based resin sheet, a polyester-based resin sheet whose anti-fog property does not decrease even after molding by heating by an indirect heating method,
It was requested.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a transparent resin sheet having no stickiness and no decrease in transparency.
An object of the present invention is to provide an antifogging resin sheet which does not deteriorate in antifogging property even after being heated by an indirect heating method and molded into various shapes such as a container shape.

[0007]

According to the present invention, a solution prepared by mixing and adjusting a polyglycerin fatty acid ester and a sucrose fatty acid ester at a ratio (weight) of 1:10 to 10: 1 on a surface of a transparent resin sheet is used. Min 0.02-0.15g / m ²
The present invention relates to an antifogging resin sheet characterized by being applied at a ratio of

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
As the raw material resin of the transparent resin sheet in the present invention, polystyrene, acrylonitrile-styrene copolymer (A
S resin), rubber reinforced polystyrene (HIPS), ABS
Examples thereof include resins, MBS resins, polyester resins such as polyethylene terephthalate and polybutylene terephthalate, polypropylene and vinyl chloride resins. Among the polyester resins, polyethylene terephthalate, which is composed of terephthalic acid as a carboxylic acid component and ethylene glycol as a glycol component, and other carboxylic acid components, 2,6-naphthalenedicarboxylic acid, isophthalic acid, Phthalic acid, adipic acid, sebacic acid, oxycarboxylic acid (for example, p-oxyethoxybenzoic acid, etc.), and other glycol components include diethylene glycol, 1,4- and 1,3-cyclohexanedimethanol, propylene glycol. , 1,
A resin in which constituent components such as 4-butanediol, neopentyl glycol, bisphenol A and bisphenol S are copolymerized is included.

The transparent resin sheet according to the present invention can be manufactured by a conventionally known manufacturing method such as the T-die method or the inflation method. Further, the transparent resin sheet of the present invention is a sheet that can be used by molding the sheet by thermoforming and is used for a molded product. Therefore, although it depends on the kind of the raw material resin, a non-oriented sheet is preferable.
In particular, a sheet made of polyester resin is a non-oriented sheet.

The antifogging resin sheet according to the present invention has a solid content obtained by combining a solution prepared by mixing and adjusting polyglycerol fatty acid ester and sucrose fatty acid ester at a ratio of 1:10 to 10: 1 on the surface of the transparent resin sheet. 0.02-0.15g /
It was applied at a ratio of m ² . Solid content 0.0
If it is less than 2 g / m ² , the antifogging property of the sheet is not improved, and if it exceeds 0.15 g / m ² , the sheet surface becomes sticky, which is not preferable. Preferably solid content 0.02
~ 0.1 g / m ² , more preferably 0.02-0.0
It is 5 g / m ² . Here, the “solid content” means a total amount of polyglycerin fatty acid ester and sucrose fatty acid ester dissolved in a solvent.

The ratio of polyglycerin fatty acid ester and sucrose fatty acid ester can be appropriately selected within the range of 1:10 to 10: 1. If the proportion of polyglycerin fatty acid ester is high, the anti-fog property after heat molding is good, but the sheet surface tends to be sticky, and if the proportion of sucrose fatty acid ester is high, the sheet surface is less sticky, but heating Although the anti-fogging property after molding tends to decrease, a solution prepared by mixing and adjusting in the above range has a solid content of 0.02 to 0.15 g.
A sheet having good anti-fogging property and non-stickiness can be obtained by coating at a ratio of / m ² .

The polyglycerin fatty acid ester of the present invention is an ester of a saturated or unsaturated fatty acid having 10 to 18 carbon atoms and polyglycerin. Polyglycerol having a degree of polymerization of 2 to 16 is used, and a degree of polymerization of 6 to 1
2 can be preferably used. Esters are monoesters in which one molecule of fatty acid is bonded to one molecule of polyglycerin, 2
It may be a diester having a molecule bound thereto or a triester having a molecule bound thereto, or may be a mixture of two or more thereof. As the fatty acid, specifically, capric acid,
Examples thereof include lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid and linoleic acid.

Specific examples of the polyglycerin fatty acid ester include diglycerin laurate (the description of laurate includes monolaurate, dilaurate and trilaurate, and the same applies to stearate and oleate hereinafter. ) Diglycerin stearate,
Diglycerin oleate, tetraglycerin laurate,
Examples thereof include tetraglycerin stearate, tetraglycerin oleate, hexaglycerin stearate, hexaglycerin oleate, decaglycerin laurate, decaglycerin stearate, and decaglycerin oleate.

The sucrose fatty acid ester of the present invention is an ester of sucrose with a saturated or unsaturated fatty acid having 10 to 18 carbon atoms. The ester may be a monoester in which a saturated or unsaturated fatty acid having 10 to 18 carbon atoms is bonded to one molecule of sucrose, a diester in which two molecules are bonded, and a triester in which three molecules are bonded, and these two or more kinds may be used. It may be a mixture. As specific examples of the fatty acid, those exemplified for the fatty acid of polyglycerin fatty acid ester can be used.

Specific examples of the sucrose fatty acid ester include:
Sucrose lauric acid ester (in the description of lauric acid ester, monolauric acid ester, dilauric acid ester and trilauric acid ester are included, and the same meaning is applied to palmitic acid ester, steariic acid ester and oleic acid ester hereinafter. ), Sucrose palmitate, sucrose stearate, sucrose oleate and the like.

When applied to the transparent resin sheet, a mixed and adjusted solution is prepared by dissolving polyglycerin fatty acid ester and sucrose fatty acid ester in a solvent at a specific ratio. As the solvent, any solvent capable of dissolving the polyglycerin fatty acid ester and the sucrose fatty acid ester may be used, and water, alcohols and the like are preferable. To produce the anti-fog resin sheet of the present invention, for example, a coating step may be added during the production step of the transparent resin sheet, or a polyglycerol fatty acid ester and a sucrose fatty acid ester may be added to the surface of the transparent resin sheet as a product. It is obtained by applying a solution dissolved in a solvent, and volatilizing and evaporating the solvent.

As the coating method, known methods such as brushing, spraying, roll coater, gravure roll coater, knife coater, rotor dampening method and dipping method can be used. The antifogging resin sheet of the present invention can be used by heating it by a direct heating method or an indirect heating method and then molding it into a desired container shape. In the direct heating method, the sheet is placed directly on the heating plate to heat it, whereas in the indirect heating method, the sheet is inserted into a heating furnace set to a predetermined temperature by a heater for a predetermined time without contacting the sheet with the heater. It is a method of indirectly heating the sheet. The sheet heated by these direct heating and indirect heating is brought into contact with a mold having a container shape, and is molded into a desired container shape by a vacuum molding method, a pressure molding method, a plug assist molding method, or the like.

[0018]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. The antifogging property of the sheet, the antifogging property of the molded product obtained by directly heating the sheet, the antifogging property of the molded product obtained by the indirect heating system, and the evaluation of the stickiness of the sheet are as follows. It carried out by the method shown.

<Anti-fog property of the sheet> 300 cc of water was placed in a 500 cc beaker, and the upper surface of the beaker was covered so that the anti-fog agent-coated surface of the sheets obtained in Examples and Comparative Examples faced downward. , Sealed. This beaker at room temperature 2
It was immersed in a constant temperature water bath installed in a room at 3 ° C, and the water temperature in the beaker was kept at 60 ° C. After 10 minutes, the condition of the water vapor condensing on the surface of the sheet was observed with the naked eye, and evaluated as follows. No water droplets 5, 5 slightly water droplets, 4 water droplets in about 20% of the total, 3 water droplets in about 50% of the total 2, the state in which water droplets are generated in about 50% or more of the whole is set as 1.

<Anti-fog property of molded articles obtained by the direct heating method or the indirect heating method> The sheets obtained by the examples and the comparative examples are (1) 2 sheets at a hot plate temperature of 95 ° C. in the direct heating method.
Heat for 2 seconds, hot plate forming machine (Kansai Automatic Forming Machine Co., Ltd., P
K-450 type) and by the pressure molding method,
In the indirect heating method, heating is performed for 6 seconds in an oven heater having an upper heater temperature of 540 ° C. and a lower heater of 330 ° C., and a vacuum forming machine (Kyoei Development Co., Ltd., FM
-2A type), the opening is 100mm by the vacuum forming method.
A container lid having a size of × 145 mm, a bottom of 70 mm × 120 mm, a height of 50 mm, and a flange of 15 mm width around the opening was formed so that the surface coated with the antifogging agent was the inside. The molded container lid was placed in a 1000 cc prismatic container with an opening of 100 mm x 145 mm, and water at 40 ° C was added to 70
The container was put in 0 cc, covered with the surface coated with the antifogging agent inside, and placed in a room at room temperature of 5 ° C. After 10 minutes, the state of condensation of water vapor on the surface of the sheet was visually observed. Evaluation,
The antifogging property of the sheet was used.

<Stickiness of Sheet> The sheets obtained in the Examples and Comparative Examples were cut into squares of 10 cm × 10 cm, and the antifogging agent-coated surface and the non-coated surface of the sheet were combined to obtain 50 kg / m ² After pressing, the sheet on the non-coated side is pasted on a flat table with double-sided tape, and the sheet on the coated side is turned 2 cm from the edge of one side of the square, and a digital push gauge (made by Aiko Engineering Co., Ltd.) ), The tensile load was measured 5 times right above, and the average value was taken as the stickiness value. The larger the value, the greater the stickiness, and the smaller the value, the smaller the stickiness.

Example 1 On one side of a non-oriented polyethylene terephthalate sheet having a thickness of 0.25 mm, 40 parts by weight of decaglycerin laurate ("Poem J-0021" manufactured by Riken Vitamin Co., Ltd.) and water 5
0.5 g of a solution prepared by mixing 6 parts by weight and 4 parts by weight of ethyl alcohol with sucrose lauric acid ester (“LWA-1570” of Mitsubishi Chemical Foods Co., Ltd.), 56 parts by weight of water, 4 parts by weight of ethyl alcohol and Solution of 40 parts by weight of sugar lauric acid ester) (2.5 g) (decaglycerin laurate: sucrose lauric acid ester = 1: 5) and water 97
An aqueous solution diluted with g was applied by a bar coater to 2 g / m ² , dried in a gear oven at 80 ° C. for 1 minute, and the solid content of decaglycerin laurate and sucrose laurate ester on the sheet surface was 0. An anti-fog resin sheet of 0.024 g / m ² was prepared. For the obtained anti-fog resin sheet, by the evaluation method described above, the anti-fog property of the sheet, the anti-fog property of the molded product obtained by directly heating the sheet, the anti-fog property of the molded product obtained by the indirect heating system. Table 1 shows the results of evaluation of the sheet properties and the stickiness of the sheet.

Example 2 In the example described in Example 1, 2.5 g of decaglycerin laurate prepared in the same manner and 0.5 g of sucrose laurate (decaglycerin laurate: sucrose laurate = 5) In the same manner as in Example 1, except that an aqueous solution prepared by diluting 1) and 97 g with water was used, the solid content of the sheet surface decaglycerin laurate and sucrose laurate ester was 0.024 g / m ² The anti-fogging resin sheet of was prepared. For the obtained anti-fog resin sheet, by the evaluation method described above, the anti-fog property of the sheet, the anti-fog property of the molded product obtained by directly heating the sheet, the anti-fog property of the molded product obtained by the indirect heating system. Table 1 shows the results of evaluation of the sheet properties and the stickiness of the sheet.

Example 3 In the example described in Example 1, 0.75 g of decaglycerin laurate prepared in the same manner and 3.75 g of sucrose laurate (decaglycerin laurate: sucrose laurate = 1) : 5) and an aqueous solution diluted with 95.5 g of water, and in the same manner as in the example, the solid content of the sheet surface including decaglycerin laurate and sucrose laurate is 0.036 g / An antifogging resin sheet of m ² was prepared. About the obtained anti-fogging resin sheet, the anti-fogging property of the sheet by the above-described evaluation method
Anti-fog property of the molded product obtained by directly heating the sheet,
Table 1 shows the evaluation results of the antifogging property of the molded product obtained by the indirect heating method and the stickiness of the sheet.

Example 4 In the example described in Example 1, 3.75 g of decaglycerin laurate prepared in the same manner and 0.75 g of sucrose laurate (decaglycerin laurate: sucrose laurate = 5) 1) and an aqueous solution diluted with 95.5 g of water were used, and the solid content of the sheet surface decaglycerin laurate and sucrose laurate ester was 0.036 g / in the same manner as in the same example. creating the antifogging resin citrate of m ^2. For the obtained anti-fog resin sheet, by the evaluation method described above, the anti-fog property of the sheet, the anti-fog property of the molded product obtained by directly heating the sheet, the anti-fog property of the molded product obtained by the indirect heating system. Table 1 shows the results of evaluation of the sheet properties and the stickiness of the sheet.

Example 5 A sheet surface was prepared in the same manner as in Example 1 except that a non-oriented polystyrene sheet having a thickness of 0.25 mm was used in place of the non-oriented polyethylene terephthalate sheet in the example described in Example 1. Solid content of decaglycerin laurate and sucrose laurate of 0. For the obtained anti-fog resin sheet, by the evaluation method described above, the anti-fog property of the sheet, the anti-fog property of the molded product obtained by directly heating the sheet, the anti-fog property of the molded product obtained by the indirect heating system. Table 1 shows the results of evaluation of the sheet properties and the stickiness of the sheet.

Comparative Example 1 In the example described in Example 1, 0.25 g of decaglycerin laurate prepared in the same manner and 1.25 g of sucrose laurate (decaglycerin laurate: sucrose laurate = 1) : 5) and a dilute aqueous solution of 98.5 g with water, and in the same manner as in the same example, the solid content of the sheet surface including decaglycerin laurate and sucrose laurate 0.012 g / creating the antifogging resin citrate of m ^2. For the obtained anti-fog resin sheet, by the evaluation method described above, the anti-fog property of the sheet, the anti-fog property of the molded product obtained by directly heating the sheet, the anti-fog property of the molded product obtained by the indirect heating system. Table 1 shows the results of evaluation of the sheet properties and the stickiness of the sheet.

Comparative Example 2 In the example described in Example 1, 3.75 g of decaglycerin laurate prepared in the same manner and 18.75 g of sucrose laurate (decaglycerin laurate: sucrose laurate = 1) : 5) and an aqueous solution prepared by diluting and with 77.5 g of water were used.
An antifogging resin sheet having a solid content of 0.180 g / m ² was prepared by combining decaglycerin laurate and sucrose laurate on the surface of the sheet. For the obtained anti-fog resin sheet, by the evaluation method described above, the anti-fog property of the sheet, the anti-fog property of the molded product obtained by directly heating the sheet, the anti-fog property of the molded product obtained by the indirect heating system. Table 1 shows the results of evaluation of the sheet properties and the stickiness of the sheet.

Comparative Example 3 In the example described in Example 1, an aqueous solution prepared by diluting 3 g of sucrose laurate with 97.0 g of water was used.
An antifogging resin sheet having a solid content of sucrose laurate ester of 0.024 g / m ² on the surface of the sheet was prepared in the same manner as in the same example. For the obtained anti-fog resin sheet, by the evaluation method described above, the anti-fog property of the sheet, the anti-fog property of the molded product obtained by directly heating the sheet, the anti-fog property of the molded product obtained by the indirect heating system. Table 1 shows the results of evaluation of the sheet properties and the stickiness of the sheet.

Comparative Example 4 Sucrose on the surface of a sheet was prepared in the same manner as in Example 1 except that an aqueous solution prepared by diluting 4.5 g of sucrose laurate with 95.5 g of water was used. An antifogging resin sheet having a solid content of lauric acid ester of 0.036 g / m ² was prepared. About the obtained anti-fog resin sheet,
By the evaluation method described above, the antifogging property of the sheet, the antifogging property of the molded product obtained by the direct heating method of the sheet, the antifogging property of the molded product obtained by the indirect heating method, and the evaluation of the stickiness of the sheet. The results are shown in Table 1.

[0031]

[Table 1]

From Table 1, the anti-fogging resin sheet according to the present invention has good anti-fogging property, and anti-fogging property by heat molding by a direct heating plate or by indirect heating method. It can be seen that the antifog property of the molded product and the stickiness of the sheet are excellent without losing the above. Comparative Example 1
Therefore, when the solid content is less than 0.02 g / m ² , the antifogging property of the sheet and the antifogging property after thermoforming are inferior.
If it exceeds 0.15 g / m ² , the sheet becomes sticky. From Comparative Examples 3 and 4, the anti-fogging resin sheet coated with only sucrose fatty acid ester on the surface is significantly increased when the sheet is heated by an indirect heating method and molded. It can be seen that the antifogging property is lowered.

[0033]

The antifogging resin sheet of the present invention does not deteriorate in antifogging property even when it is heated and molded by an indirect heating method, has good stickiness, and has good transparency.

Claims (5)

(57) [Claims] 1. A transparent resin sheet (however, a polystyrene resin
A solid content of 0.02 to 0.15 g of a solution prepared by mixing and adjusting a polyglycerin fatty acid ester and a sucrose fatty acid ester in a ratio of 1:10 to 10: 1 on the surface of the fat sheet).
An anti-fog resin sheet characterized by being applied at a ratio of / m ² . 2. The antifogging resin sheet according to claim 1, wherein the transparent resin sheet is a polyester resin sheet. 3. A transparent resin sheet made of polystyrene resin.
Polyglycerin fatty acid ester and sucrose fat on the surface
Acid ester with polyglycerin fatty acid ester 1
Then, the sucrose fatty acid ester is more than 1 and 10 or less
In the ratio of 0.02 to 0.
An antifogging resin sheet, characterized by being applied at a rate of 15 g / m ² . 4. Based on 1 polyglycerol fatty acid ester
The ratio of sucrose fatty acid ester is 5 or more and 10 or less
It is characterized in that it is formed by applying a mixed and adjusted solution.
The antifogging resin sheet according to claim 3. 5. A polyglycerin fatty acid ester is decag.
4. Lyserine laurilate.
Alternatively, the antifogging resin sheet according to item 4.