JPH09295384A - Styrene resin sheet roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin sheet roll which gives properties such as anticloudiness, mold-releasing and lubricity to a styrene resin sheet and its molded container and is almost free from the generation of whitening in a molding, and further, can be formed into a highly transparent container as well as a method for manufacturing the resin sheet roll. SOLUTION: When a sheet roll is rolled back, one of its faces is coated with 5-50mg/m<2> of cane sugar fatty acid ester and silicon oil applied to the surface of the anticlouding agent, arranged in that order, on the surface of a styrene resin. On the other hand, the other face is coated substantially with only the silicon oil. The amount of the silicon oil on the anticlouding agent is 0-48% for the total silicon oil amount of 1-50mg/m<2> . Besides corona treatments 3, 4-1, 4-2 and two-stage drying steps 6, 8, 9 are combined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-fog styrene resin sheet roll which is mainly thermoformed by a hot plate contact heating vacuum pressure forming method and is used as various packaging containers such as food packaging containers. The manufacturing method is related.

[0002]

2. Description of the Related Art Conventionally, it is disclosed in JP-A-53-11 that a styrene resin sheet is coated with an antifogging agent and silicone oil to impart antifogging property and improve slipperiness and releasability.
5781, JP-B-61-36864, JP-B-63-62538, JP-A-5-287097 and the like are well known.

In these methods, a mixture of an antifogging agent containing sucrose fatty acid ester as a main component and a silicone oil is used in order to impart antifogging property, slipperiness and releasing property to a styrene resin sheet. Liquid is applied on one side. For example, in JP-A-53-115781, the surface tension is adjusted to 40 to 55 dynes / cm by corona discharge treatment for the purpose of simultaneously improving nonblocking property and antifogging property.
A method has been proposed in which the antifogging agent and the silicone oil are evenly attached. Further, JP-B-61-36864 discloses that the surface tension of the sheet surface is 50 by corona discharge treatment for the purpose of improving antistatic property as well as antifogging property and releasability.
A method of applying a mixed solution of sucrose fatty acid ester, silicone oil, and coconut oil fatty acid diethanolamide after adjusting to -60 dynes / cm has been proposed. Further, JP-B-63-62538 and JP-A-5-287097.
Japanese Patent Laid-Open Publication No. 1993-242242 discloses an anti-fog film (sucrose fatty acid ester coating film) with improved continuous anti-fog property and at the time of thermoforming, especially during deep drawing.
A method of applying a mixture of sucrose fatty acid ester, hydrophilic polymer and silicone emulsion to a styrene resin sheet for the purpose of preventing breakage of the release film (silicone emulsion coating film) and improving the anti-fog property of the molded product. Is proposed.

The sheet coated by such a method is usually wound into a roll and then thermoformed, which is used in a large amount as various containers such as food packaging for forming food containers. As a thermoforming method for a styrene resin sheet, particularly a biaxially stretched sheet, a method called hot plate contact heating vacuum pressure forming (hereinafter referred to as hot plate pressure forming) is generally adopted. In most thermoforming methods, the sheet stretched in the space is heated by non-contact such as radiant heating, but in this method, the sheet is adhered to the hot plate by the pneumatic pressure from the mold side and the vacuum pressure from the hot plate side. Then, the heated sheet is immediately pressed by the compressed air pressure from the hot plate side and the vacuum pressure from the mold side to be pressed against the mold and molded. At this time, the anti-fogging surface of the sheet is generally on the inside of the molding container, that is, on the hot plate contact side.

The above-mentioned conventional invention was made mainly to impart anti-fogging property and releasability to a styrene resin sheet molded into a container by a hot plate pressure molding method.

[0006]

Polystyrene-based resin sheets, particularly biaxially-stretched polystyrene-based sheets, are characterized by their high transparency, luster, and stiffness (rigidity) as compared with sheets of other materials. It is widely used for various packaging materials including applications. However, a polystyrene resin sheet coated with a conventional antifogging agent and silicone oil and applied to the surface of the sheet has excellent transparency and gloss at the sheet stage, but whitening occurs in a molding container after hot plate pressure molding. There is a defect that transparency is lowered due to the generation of a pattern and a poor appearance (hereinafter, this phenomenon is referred to as molding whitening) often occurs, and the characteristic transparency and gloss are lowered.

It is an object of the present invention to provide a styrene resin sheet roll which does not cause such a molding whitening phenomenon and a method for producing the same.

[0008]

Means for Solving the Problems As a result of diligent studies, the present inventor has found that the whitening of the styrene resin sheet during hot plate pressure molding is caused by the surface of the styrene resin sheet hot plate contact surface and the silicone oil during molding heating. It has been found that it is more likely to occur due to the interaction with and, and based on this knowledge, further studies have been completed to complete the present invention.

That is, according to the present invention, an antifogging styrene resin sheet coated with the antifogging agent and silicone oil on opposite surfaces with the coating amounts of (1) and (2) below has a winding tension of 1
In a styrene resin sheet roll wound at 0 to 40 kg / m, when the sheet roll is rewound, the following (3)
Styrenic resin sheet roll satisfying the following conditions: (1) The coating amount of the antifogging agent is 5 to 50 mg / m ² .

(2) The amount of silicone oil applied is 1 to 5
0 mg / m ² .

(3) A / (A + B) is 0 to 0.48.

(Where A is the coating amount of silicone oil on the antifogging agent and B is the coating amount of silicone oil on the opposite surface) Further, as a method for producing the same, the antifogging agent and the silicone oil are provided on the opposite surfaces as follows (1). , The anti-fogging styrene resin sheet coated with the coating amount of (2) is wound and the tension is 10 to 40.
A method for producing an anti-fog styrene-based resin sheet roll which is a styrene-based resin sheet roll wound at kg / m, and which satisfies the following (3) when the sheet roll is rewound. Wetting coefficient 45 on both sides
After corona treatment to ~ 65 dynes / cm, apply antifogging agent aqueous solution or silicone emulsion and dry for one step, and then perform corona treatment on the remaining opposite surface in the same manner (omitted if already double-sided corona treatment). A clouding agent aqueous solution or silicone emulsion (different from the opposite surface) is applied, dried in two steps and sufficiently dried, and then the winding tension is 10 to 4 with a winder.
The present invention relates to a method for producing an antifogging styrene-based resin sheet roll, characterized in that the resin sheet roll is wound under the condition of 0 kg / m.

(1) The coating amount of the antifogging agent is 5 to 50 mg /
m ² .

(2) The amount of silicone oil applied is 1 to 5
0 mg / m ² .

(3) A / (A + B) is 0 to 0.48.

(Where A is the coating amount of silicone oil on the antifogging agent and B is the coating amount of silicone oil on the opposite surface). The details will be described below.

In the sheet roll of the present invention, when the sheet roll is rewound, one side of the sheet roll has a styrene resin on which an antifogging agent is added.
˜50 mg / m ² and further coated with silicone oil 0 to 24 mg / m ² (hereinafter, this surface is referred to as an anti-fog surface), that is, the anti-fog surface of the sheet roll of the present invention is The feature is that an antifogging agent is interposed between the styrene resin and the silicone oil so that the styrene resin and the silicone oil do not come into direct contact when they are rewound, and the transfer amount is controlled (using a masking film). . Thus, in the sheet roll of the present invention, when rewound, one surface is coated with an antifogging agent in that order from the resin surface, and further coated with silicone oil, and the other surface is substantially coated with only silicone oil. With this configuration, it is possible to prevent the interaction between the styrene resin and the silicone oil by direct contact, and to maintain the transparency and gloss of the styrene resin sheet at a high level, which is the object of the present invention (mold whitening is less likely to occur. It is possible to supply containers. On the other hand, in a conventionally known sheet, an antifogging agent and silicone oil are mixed and coated on a styrene resin. That is, in the conventionally known sheet, since the silicone oil and the styrene resin are in direct contact with each other, even if the coating amounts of the antifog agent and the silicone oil are the same as those of the sheet of the present invention, the styrene resin and the silicone oil are Due to the above interaction, the thermoformed product obtained by the hot plate pressure air forming method has a drawback that whitening easily occurs.

For example, when the sheet roll of Example 1 and the sheet roll of Comparative Example 1 were not molded, the sheet numerical values were evaluated by the same method as the molding whitening evaluation method carried out in Examples as they are. The maximum line value for both sheets is 180 on average
Was equivalent to However, the maximum line numerical value of the container after hot-plate air-pressure molding shows an average of 110 in the molded container from the sheet roll of Example 1 and an average of 50 in the molded container from the sheet roll of Comparative Example 1. Met. From these results, the drawbacks of the above-mentioned conventional sheet and the effects of the present invention are clear.

In the sheet roll of the present invention, for example, one side of the sheet is corona-treated and then coated with an anti-fog agent, and the opposite side is coated with silicone oil, and the sheet is rolled into a silicone roll. Obtained by controlling the transfer of oil onto the antifog surface. This makes it possible to prevent the transfer of the antifogging agent to the opposite surface by corona-treating the sheet roll resin surface to make it hydrophilic and to uniformly coat the sheet roll resin surface with the antifogging agent. .

In the sheet roll of the present invention, the concept of two-stage drying is adopted, and it is sufficiently dried before being wound into a roll, and in combination with corona treatment of the sheet surface, the transfer amount of silicone oil is controlled, and This is achieved by accurately and uniformly controlling asymmetric transfer on both sides.

Next, the sheet roll of the present invention will be described.

The amount of the antifogging agent that directly covers one surface (antifogging surface) of the sheet roll of the present invention is 5 to 50 mg / m ² . If the coating amount of the antifogging agent is less than 5 mg / m ² , a sufficient antifogging effect cannot be obtained and the thickness of the silicone oil as a masking film is insufficient, so that a part of the silicone oil directly contacts the styrene resin. This is an area that may cause whitening during molding. Further, when the antifogging agent is coated in an amount of more than 50 mg / m ² , no improvement in antifogging property is observed, and further,
This is an area in which the transparency of the sheet is deteriorated due to stickiness of the sheet or the thermoformed product, blocking, and excessive coating of the antifogging agent. Also, especially for sheet rolls, the drawing ratio (depth of molded product /
When used in a thermoformed product having a molded product having an opening short side length or diameter of 0.2 or more, it is preferably coated with 10 mg / m ² or more from the viewpoint of maintaining anti-fogging persistence after molding, and From the viewpoint of not deteriorating the color tone of the recycled polymer of the sheet (preventing yellowing), the coating amount of the antifogging agent is preferably 30 mg / m 2.
² or less.

The total amount of silicone oil coated on the front and back of the rewound sheet is 1 to 50 mg / m ² . Below this lower limit, for example, apply silicone oil on one side,
Even if an attempt is made to obtain the sheet roll of the present invention by transfer, the silicone oil is not transferred or is difficult to transfer uniformly, and this is also an area where the mold releasability between the mold or the hot plate and the sheet is deteriorated during thermoforming of the sheet. On the other hand, when the amount exceeds the upper limit, blocking of the sheet and stickiness of the sheet or the thermoformed product are felt, and the commercial property is deteriorated. Further, from the viewpoint of improving the releasability of a thermoformed sheet without a stack, it is preferable that the total amount of silicone oil coating be 5 mg / m ² or more. Also, transfer of silicone oil to a hot plate of a molding machine or a mold. From the viewpoint of minimizing the contamination by the above, the total amount of silicone oil coating is preferably 20 mg / m ² or less.

[0024] Further, the silicone oil coverage Amg / m ² on the anti-fogging agent-coated surface, the ratio A / (A + B) of the silicone oil coverage Bmg / m ² on the opposite surface is 0 to 0.4
It is 8, preferably 0.05 to 0.48, and more preferably 0.1 to 0.35.

In the present invention, the silicone oil coated on the antifogging agent is 0 to 24 in the area satisfying the above relationship.
mg / m ² . However, when the silicone oil coating amount is less than 0.05 mg / m ² , the sheet easily sticks to the hot plate during hot plate pressure forming, the surface of the sheet is roughened, and the resulting thermoformed product is The appearance may deteriorate, so it is preferable to set it to 0.05 mg / m ² or more. When the silicone oil is coated over 24 mg / m ² , the silicone oil film is too thick and has anti-fogging properties. In addition, the masking effect on the sheet surface by the anti-fog agent becomes insufficient, and the sheet and silicone oil partially contact due to the contact pressure of the hot plate during hot air plate forming, causing whitening of the molding. Therefore, it is preferably 24 mg / m ² or less. Further, from the viewpoint of improving the releasability between thermoformed products of the sheet and preventing hot plate contamination due to transfer of silicone oil to the hot plate of the molding machine, the silicone oil coating amount is 0.1 to 17.5 m.
It is more preferably g / m ² , and even more preferably 0.25 to 10 mg / m ² .

The surface opposite to the anti-fog surface is substantially coated with only silicone oil, and the silicone oil coating amount is 0.52 to 50 m in the area satisfying the above relationship.
It is in the range of g / m ² . 0.52 m of silicone oil
If it is less than g / m ² , the releasability between the sheet and the molding die is deteriorated at the time of thermoforming, and if it exceeds the upper limit, it is not only a region where stickiness is felt, but also the mold becomes heavily soiled. The transparency of the molded product decreases. From the viewpoint of further improving the releasability of the thermoformed products of the sheet and preventing the contamination of the mold by the transfer of silicone oil to the mold,
Silicone oil coverage is 0.75-37.5mg / m
² is preferable, more preferably 2.5 to 20 m
g / m ² . Here, "substantially coated with only silicone oil" means that the amount of the components other than the emulsifier derived from the silicone oil and the silicone emulsion is at a level not quantified by the analysis method described later (anti-fogging agent). Is outside the quantitation limit). Thus, in the present invention, when the sheet roll is rewound, the coating amount of silicone oil is not targeted on both sides, and the coating amount of silicone oil on the anti-fog surface side is necessary for the releasability of the hot plate surface and the sheet. The necessary amount of coating is required for the releasability from the mold and the peelability and slipperiness when taking out one by one during use after stacking during transportation of the molded products. Has been secured.

The sheet of the present invention is coated, for example, on one side with an antifogging agent and on the other side with silicone oil by the method described below and wound into a roll with a winding tension of 10 to 40 kg / m. It can be obtained by transferring onto the antifogging agent film applied on the opposite surface. In this case, the transfer amount of the silicone oil to the antifogging surface changes with time, and it takes 5 days or more at 23 ° C. to equilibrate the transfer amount. Therefore, the silicone oil coverage of the sheet of the present invention is preferably measured by aging the sheet roll at 23 ° C. for 5 days or longer and then rewinding the roll.

The silicone oil coating amount can be quantitatively analyzed by a fluorescent X-ray analysis method, an FTIR analysis method (ATR) or the like. In addition, quantitative analysis of the coating amount of antifog agent
The film can be washed, and the washing liquid can be collected and used by a method such as a gravimetric method, a gas chromatography method, a high performance liquid chromatography method, or an FTIR analysis method (ATR method).

The antifogging agent used in the present invention is a nonionic surfactant, for example, sucrose fatty acid ester, polyglycerin fatty acid ester, polyoxyethylene alkylphenyl ethers, polyoxyethylene alkyl ether. One or a mixture of surfactants selected from the group consisting of polyoxyethylene fatty acid ethers, polyoxyethylene fatty acid esters, sorbitan fatty acid esters, polyoxyethylene sorbitan fatty acid esters, etc., having an HLB of 11 to 17. . HLB
Is less than 11, the water resistance, dispersibility, and wettability of the antifogging agent are deteriorated, and it is difficult to form a uniform antifogging agent film. On the other hand, when HLB exceeds 17, it is a region where the continuous antifog property is deteriorated because the antifog agent is easily washed by water. Among these, as the antifogging agent of the polystyrene-based resin sheet that is frequently used for food packaging applications, sucrose fatty acid ester, polyglycerin fatty acid ester, and sorbitan fatty acid ester that are approved as food additives are preferable, and among them,
Sucrose fatty acid ester containing 50 mol% or more of lauric acid as a fatty acid component, and the sucrose fatty acid ester (9
A mixture of 9 to 50% by weight) and polyglycerin fatty acid ester or sorbitan fatty acid ester (1 to 50% by weight) is particularly preferable because it has an excellent balance of product safety and antifogging property and an excellent masking effect of silicone oil. (When the polyglycerin fatty acid ester is mixed in an amount of more than 100% by weight or 50% by weight, the masking effect is slightly lowered, and the molding whitening prevention effect tends to be poor).

The silicone oil used in the present invention is an organic polysiloxane such as dimethylpolysiloxane, methylphenylpolysiloxane and diphenylpolysiloxane, and dimethylpolysiloxane is particularly preferred in terms of product safety and economy. The viscosity of the silicone oil is preferably 100 to 100,000 CS,
This upper limit is for ensuring the stability of the emulsion when silicone oil is used in the emulsion, and the lower limit is the level necessary for improving the slipperiness of the sheet and the peelability between the hot plate and the sheet. Further, in order to improve the releasability between thermoformed products and prevent the mold from being contaminated with silicone oil, it is preferable to use a silicone oil having a viscosity of 500 to 50,000 CS, more preferably 10
It is 00 to 20000 CS. For these silicone oils, known silicone emulsions are preferably used from the viewpoints of easy handling and easy coating.

Next, the method for producing the styrene resin sheet roll of the present invention will be described with reference to FIG. Although FIG. 1 is a schematic diagram of an example of the manufacturing method of the present invention that is off-line, a set of coating devices may be incorporated in the sheet film-forming line to manufacture by on-line coating. In FIG. 1, 1 is a roll of sheet roll, 2 is a styrene resin sheet, 3 and 4 are corona treatment machines, 5 and 7 are coaters, 6 and 8 are first-stage dryers, and 9 is second-stage drying. Machine 10 represents the sheet roll after coating.

The method of manufacturing the sheet roll of the present invention is such that after the sheet is formed (film formation), the wetting coefficient is 45 by the corona treatment machines 3 and 4.
After corona treatment to ~ 65 dynes / cm, the coater 5 applies the anti-fogging agent aqueous solution or silicone emulsion, and the dryer 6 performs one-step drying, and the coater 7 further coats the anti-fogging agent aqueous solution or silicone emulsion (different from the opposite surface). ) Is applied and sufficiently dried by the dryers 8 and 9, and then the resin sheet roll 10 is wound by the winding machine under the condition of the winding tension of 10 to 40 kg / m. It is also possible to change the corona treatment device 4-1 in FIG. 1 to the position of 4-2, perform corona treatment on one side, and after completion of coating, perform corona treatment on the opposite side. In this manufacturing method,
In particular, the corona treatment and the drying method are important and are a feature of the present invention.

In the production method of the present invention, the drying after the application of the antifogging agent aqueous solution and the silicone emulsion is performed so that the silicone oil is uniformly transferred when a part of the silicone oil is transferred onto the antifogging agent at the time of winding the roll. Must be done well. If the water is not sufficiently dried, the transfer of the silicone oil becomes non-uniform, so that the desired styrene resin sheet roll cannot be obtained.

Therefore, the drying method employed in the manufacturing method of the present invention is, for example, after coating one side, drying is normally performed by the dryer 6 (one-stage drying), then coating is performed on the opposite side, and the coating surface is dried. After being dried normally by 1 (drying in one step) by 8, the material is dried again by passing through the dryer 9 in two steps. By performing such two-step drying, the moisture taken in the antifogging agent and the emulsifier in the silicone emulsion is more completely dried, and the drying level of the antifogging agent and silicone oil coated surface is improved and evenly distributed. To be dried. As a result, it becomes possible to control the uniformity of the transfer amount of the silicone oil to the antifogging surface, and a substantially uniform transfer silicone film is formed on the antifogging agent. On the other hand, in the conventionally known generally known drying method (when the two-step drying is not performed), the drying is not sufficient, and in this case, non-uniformity occurs in the transfer of the silicone oil. Is difficult to obtain stably (for example, the difference between Example 6 and Comparative Example 7 in Table 3).

The drying conditions of the coated sheet greatly vary depending on the coating amount of the coating solution, the sheet production rate and the like and cannot be specified unconditionally, but normally, to dry the solvent (water) of the coating agent, 100-13
Generally, it is passed through a warm air dryer at 0 ° C. for about 5 to 20 seconds. Also in the present invention, it is preferable to select the conditions under which water is normally evaporated in the dryers 6 and 8 and to further perform two-stage drying by the dryer 9 under the same conditions as the dryers 6 and 8. In FIG. 1, the dryers 8 and 9 are separated, but one dryer having a length more than twice as long as the dryer 6 is used for one-stage drying and two-stage drying.
It is also possible to perform stage drying. The type of dryer is not particularly limited, but a warm air dryer is generally used.

In the corona treatment, the surface tension of the sheet is I
Wetting coefficient measured according to SO 8296 45-6
Adjust to 5 dynes / cm (mN / m) and implement. If the wetting coefficient is less than 45 dynes / cm, the aqueous solution of the antifogging agent and the silicone emulsion are not uniformly coated, resulting in uneven coating, resulting in nonuniform antifogging properties and releasability. When the surface tension exceeds 65 dynes, blocking is likely to occur, and static electricity is more likely to occur at the time of sheet production and sheet molding in an environment of low temperature and low humidity. In addition, since silicone oil is transferred to the antifogging surface, it is necessary to coat the surface uniformly, and the wettability is lower than that of the antifogging agent. Therefore, the silicone emulsion application surface is 50 to 65 dynes / cm.
Is particularly preferable. The corona treatment may be performed before coating with the treatment liquid and is not particularly limited.

The method of coating the antifogging agent and the silicone oil is not particularly limited, and a generally known method such as a spray coater, a gravure coater, an air knife coater, a roll coater or a knife coater can be used. At this time, the concentration of the antifogging agent aqueous solution is 0.05% to 5%.
% Is suitable, and about 1 to 10 g / m ^{2 of} wet coating is suitable. Also silicone emulsion,
It is suitable to dilute with water to a silicone oil concentration of 0.01 to 4% and similarly apply it with a wet coating on the surface opposite to the antifogging surface at about 1 to 10 g / m ² . Further, for the purpose of preventing foaming of the antifogging agent at the time of coating, a surfactant having an HLB of 1 to 8 as an antifoaming agent, such as sorbitan fatty acid esters, polyoxyethylene polyoxypropylene block copolymers, etc., Particularly preferably, a sorbitan fatty acid ester which is a food additive is used as an antifogging agent 10
You may add 5-30 weight part with respect to 0 weight part.

The order of coating is not particularly limited. For example, a method in which an antifogging agent is first applied and then dried, a silicone emulsion is applied to the opposite surface, and two steps are dried, or a silicone emulsion is applied first After drying, an anti-fogging agent may be applied to the opposite surface and the two-step drying may be similarly performed.

The sheet coated with the coating agent is dried and then used as a winding sheet roll with a winding tension of 10 to 40 kg / m. When the winding tension is less than 10 kg / m, the sheet is likely to be misaligned, and the sheet roll is likely to have a bamboo-like shape, or the sheet roll is likely to be damaged during transportation. On the other hand, if the winding tension exceeds 40 kg / m, the paper tube is likely to be crushed and the gauge band is likely to be strongly generated, and waviness is likely to occur at the time of rewinding. More preferably, the sheet is wound by the above method, aged for 1 to 3 days, then rewound into a sheet roll, and rewound into a roll with a winding tension of 10 to 40 kg / m. There is a difference in the transfer speed of silicone oil between the core of the sheet roll and the surface of the roll, but it is necessary to rewind (rewind the sheet roll wound on the roll once into a sheet and then wind it on the roll again). By doing so, the transfer of the silicone oil on the entire sheet roll can be balanced in a short time.

The styrene resin used in the styrene resin sheet roll of the present invention is a homopolymer of styrene monomer selected from styrene, alkyl styrenes, halogenated styrenes and the like, and copolymers thereof.
And a block, random, or graft copolymer of a rubber component such as a conjugated diene (butadiene, isoprene, etc.), a styrene-conjugated diene copolymer, and the above styrene-based monomer,
Further, it is a copolymer of the above-mentioned styrene-based monomer and another monomer and a rubber graft copolymer thereof. Further, known additives such as plasticizers such as mineral oils, terpenes and petroleum resins, antistatic agents, and ultraviolet absorbers may be added to these styrene resins.

Of these, preferred resins are styrene homopolymers (GPPS), styrene-methacrylic acid copolymers, styrene-maleic anhydride copolymers, styrene-
Styrene-alkyl (meth) acrylate copolymers such as butyl (meth) arylate copolymer and GP with these
Blend with PS, styrene-conjugated diene block copolymer (SBBC), SBBC with GPPS and styrene-
Blends with alkyl (meth) acrylate copolymers and the like.

The sheet material used in the styrene resin sheet roll of the present invention may be a single layer sheet made of the above styrene resin or a known multilayer sheet containing one or more layers of the above styrene resin. Examples of the multilayer sheet include GPPS (surface layer) / GPPS + SBBC (inner layer),
Heat-resistant styrene-based copolymers (surface layer) / GPPS (inner layer), GPPS (surface layer) / styrene-alkyl (meth) acrylate copolymers (inner layer), high molecular weight GPPS (surface layer) such as styrene-methacrylic acid copolymer ) / Medium to low molecular weight GPPS (inner layer), GPPS + SBBC (surface layer) / G
PPS (inner layer), GPPS (surface layer) / plasticized GPPS
2 layers, 3 layers, or 4 by combination of layers such as (inner layer)
Known sheets having more than one layer can be used. In addition, the original sheet is
It may be unstretched or may be uniaxially or biaxially stretched, and may be appropriately selected depending on the desired physical properties of the sheet / film. Stretching may be performed by a known bubble method, a tenter method, or the like and is not particularly limited. The unstretched sheet may be produced by a known method without any limitation.

[0043]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below with reference to Examples.

EXAMPLES The performance evaluation of the sheets and films in Examples and Comparative Examples was carried out according to the following criteria (“∘” or higher is the pass level of the present invention unless otherwise specified).

(1) Molding Whitening 80 mm × 130 mm × 15 mm by hot plate pressure molding
Mold a lid with a flat top part (set the sheet so that the anti-fog surface of the sheet becomes the hot plate contact surface. The sheet of Production Example 1 had a heating temperature of 132 ° C., a heating time of 1.2 seconds, and a molding cycle 6 Molded in seconds. The sheet of Production Example 2 was randomly selected from a molded product having a heating temperature of 108 ° C., a heating time of 2.2 seconds and a molding cycle of 8 seconds), and stains other than whitening of the molding and scratches. 1
The top part of 0 molded product was cut out, overlapped, and the peripheral part was fixed with a tape to obtain a test piece. Next, a line number meter published by the Printing Society of Japan is placed on the table, a test piece is placed 10 cm above the line number, and the maximum number of lines that can be visually discerned from the position 20 cm above the test piece is measured. = 4, a total of 20 samples were tested), and the molding whitening was evaluated from the average value (rounded to the nearest whole number). The smaller the value, the more intense the whitening of the molding.

(2) Moldability (adhesion between sheet and hot plate, releasability between sheet and mold, mold stain) A container was molded by the same method as the molding whitening measuring method. From the appearance evaluation of the obtained molded product, the adhesion between the sheet and the heat plate (surface roughness of the molded product's anti-fog surface, the occurrence of adhesive marks), the releasability between the sheet and the mold (the generation of noise during release, The following criteria were used to evaluate scratches due to defective release) and mold stains (the number of shots until stains and concave marks were formed on the non-fog-proof surface of the molded product).

Adhesion between the sheet and the heat plate ◎: Adhesion-free surface on the anti-fog surface, no adhesive marks ×: Adhesion marks occur on the anti-fog surface ・ Releasability between sheet and mold ◎: Sound at release No noise is generated and the molded product is not scratched. ○: A little loud noise is generated at the time of mold release, but there is no scratch on the molded product. ×: Large noise is generated at the time of mold release or the molded product is scratched. ◎: No mold stain on 2000 shots or more ○: Mold stain occurs on 1500 to 1999 shots Δ: Mold stain occurs on 1000 to 1499 shots ×: Mold stain occurs on 999 shots or less (3) Antifogging 85 ± 1 On a constant temperature water tank controlled at ℃, 40 mm from the water surface, with a drawing ratio of 0.1 (80 mm × 130 mm × 8 mm) and a drawing ratio of 0.3 (90 mmΦ × 27 mm) so that the anti-fog surface is on the water surface side. Place the molded product and after 3 minutes (initial anti-fog property) 1 hour after the attachment of the water droplets of the (sustained antifog) were evaluated by the following criteria. Molded product with a drawing ratio of 0.1
The above-mentioned anti-fogging property is a minimum acceptable level, and a molded product having a drawing ratio of 0.3 is preferably an anti-fogging property of O or more.

⊚: A mirror-like water film was observed on the entire surface, and the entire surface was transparent glass-like, and the inner surface was completely transparent.

◯: A partially continuous water film is seen, and the whole is slightly “moggy”, but there are no water droplets and the inside is clearly visible.

Δ: Large water droplets with a diameter of about 10 to 20 mm are seen, and the inside is slightly difficult to see.

X: Small water droplets of about 5 mm or less were observed in 10% or more of the entire area, and the inside was very difficult to see.

(4) Releasability of molded product Eight sets of hood packs (the inner surface of the pack was an anti-fog surface) were molded from a test sheet using a hot plate heating type air pressure molding machine and punched by stacking 25 shots. The peelability of the main body when the hood portions were lifted one by one after stacking and leaving for 1 minute was evaluated according to the following criteria ◎: Good peelability in a molded product of 98% or more: Good peelability ○: 90% The above molded products can be well peeled off and are not lifted up by stacking four or more sheets: There is a practical level of peelability. Δ: 80 to 90% of molded products can be well peeled off, or 9
It is good at 0% or more, but may be lifted up by stacking four or more sheets: Poor peelability (however, it may be practical depending on the shape of the molded product).

X: Less than 80% of molded products that can be peeled off satisfactorily: No peeling property (5) Blocking resistance of the sheet A4 size sheet is so contacted between the anti-fog agent-coated surface and the anti-fog agent-uncoated surface. 5 sheets on top of each other, 200k at 60 ℃
The sheet was peeled off after being treated under a pressure of g / cm ² for 3 minutes and evaluated according to the following criteria ◎: Peeling without resistance and no whitening ○: Some resistance but peeling without whitening △: Peeling Possible but the sheet becomes white x: The sheet adheres and cannot be peeled off or the sheet is torn (6) Quantification of silicone coating amount Red on the surface of the sheet by ATR method (ATR crystal ZnSe, integration number 16 times) using FTIR The external absorption spectrum was measured, and the absorption of silicone oil (dimethylpolysiloxane) at about 1263 cm ~ ¹ and that of polystyrene (about 137 cm)
The amount of silicone coating was quantified from the ratio of 2 and 1069 cm- ¹ (using a standard curve of known concentration to prepare a calibration curve for quantification).

(7) Transfer Uniformity of Silicone Oil Two random measurement samples were prepared from 10 m ^{2 of} antifogging surface of the sheet.
Cutout at 0 point, the silicone coating amount was quantified by the FTIR method, and the uniformity of transfer was evaluated based on the variation of the coating amount (transfer amount) according to the following criteria.

⊚: Variation in silicone oil coating amount within ± 15% of average ◯: Variation in silicone oil coating amount ±± with respect to average
15 to ± 30% ×: Variation in silicone oil coating amount is ± with respect to the average
Greater than 30% (8) Quantification of antifogging agent coating amount The difference spectrum between the sheet surface and polystyrene was measured by the ATR method (ATR crystal ZnSe, 64 times of integration) using FTIR, and the silicone coated with the antifogging agent was measured. Using the oil as an internal standard (determining the amount of silicone oil in the same manner as in (6) above), the characteristic absorption of the carbonyl group of the antifogging agent (about 1735 cm ~ ¹ : in the case of sucrose fatty acid ester)
The amount of antifogging agent was quantified.

The following antifogging agents were used.

B-1: Sucrose fatty acid ester, 68 mol% of lauric acid as a fatty acid component and 3 of monoester
0 mol%, HLB 15.2 B-2: decaglycerin lauric acid ester, 66 mol% monoester, HLB 13.2 B-3: hexaglycerin lauric acid ester, 62 mol% monoester, HLB was 15.4, and the following silicone oil was used.

S-1: Dimethylpolysiloxane (viscosity: 5000 cs, emulsion having an effective solid content of 30% by weight) S-2: Dimethylpolysiloxane (viscosity: 1000 c)
s, an emulsion having an effective solid content of 30% by weight) S-3: dimethylpolysiloxane (viscosity 50000c)
s, emulsion having an effective solid content of 30% by weight) Production Example 1 Polystyrene is supplied to an extruder and extruded from a T-die.
After casting the extruded sheet, it was longitudinally stretched 3 times at a speed ratio of a roller heated to 130 ° C., and then horizontally stretched 3 times with a tenter at an oven temperature of 135 ° C. to obtain a thickness of 0.1.
An 8 mm biaxially stretched sheet was obtained.

Production Example 2 Styrene-butyl acrylate copolymer (styrene 87
%) And a styrene-butadiene block copolymer (70% by weight of styrene) in a weight ratio of 55/45, supplied to an extruder, extruded from a T-die, and the extruded sheet cooled with a casting roll. Thickness 0.3 mm
A non-stretched sheet of was obtained.

Example 1 One side of the sheet manufactured as a trial in Production Example 1 was corona-treated so that the wetting coefficient was 63 dynes / cm, and a 96-fold diluted aqueous solution of silicone oil S-1 (silicone oil concentration of 0. 3125% by weight) was applied by a spray coater at 4 g / m ² (silicone oil 12.5 mg / m ² ) and then passed through a hot air dryer at 120 ° C. for 8 seconds.
Next, the opposite surface was subjected to corona treatment so that the wetting coefficient was 58 dynes / cm, and then a 0.5 wt% aqueous solution of the antifogging agent B-1 was applied to this surface with a spray coater at 4 g / m ² (20 mg / fogging agent. m ² ) After coating, it was passed through a hot air dryer at 120 ° C. for 8 seconds, and then passed through a hot air dryer at 120 ° C. for 8 seconds (two-stage drying). 15 ~ the obtained sheet
A sheet roll was obtained by winding with a winding tension of 20 kg / m. After aging the sheet roll for 1 day at 23 ° C, the sheet is rewound (winding tension at the time of rewinding 15 to 20 kg).
/ M) Aged at the same temperature for 4 days. After aging, transfer of the antifogging agent was not confirmed, and the silicone oil was coated on the surface coated with the antifogging agent on average of 4.2 mg / m ² and on the surface coated with the silicone oil on average of 8.3 mg / m ^2. It was confirmed by FTIR (ATR method). The results of evaluating the physical properties of this sheet are shown in Table 1.

Examples 2 to 4 Corona treatment strength of silicone coated surface was 56 dyne / c.
m, the corona treatment strength of the antifogging agent coated surface is 60 dynes / c
m, and the concentration of the antifogging agent aqueous solution is 0.2% by weight (the antifogging agent 8
mg / m ² : Example 2), 0.4 wt% (anti-fog agent 16 m
g / m ² : Example 3), 1.0% by weight (36 mg of antifogging agent)
/ M ^2: addition to the Example 4) is performed in the same manner as in Example 1 to obtain a sheet roll. No transfer of the antifogging agent was confirmed after aging in any of the sheets, and the silicone oil was coated on the surface on which the antifogging agent was applied at an average of 4.3 mg / m ^2, and on the surface where the silicone oil was applied, at an average of 8.2 mg / m ^{2. It} was confirmed by FTIR (ATR method) that ^two coats were formed. The results of evaluating the physical properties of this sheet are shown in Table 1.

Examples 5 to 7 The dilution ratio of silicone oil was 480 times (silicone oil application amount 2.5 mg / m ² : Example 5), 60 times (silicone oil application amount 20 mg / m ² : Example 6), Three
A sheet roll was obtained in the same manner as in Example 1 except that the coating amount was 0 times (silicone oil application amount 40 mg / m ² : Example 7). No transfer of the anti-fog agent was confirmed after aging, and the silicone oil was 0.4 / 2.1, 6.4 / average in the order of the anti-fog agent coated surface / silicone oil coated surface from Example 5.
It was confirmed by FTIR (ATR method) that coating was carried out at 13.6 and 16.8 / 23.2 mg / m ² . The results of evaluating the physical properties of this sheet are shown in Table 1.

Example 8 One side of the sheet prepared in Production Example 1 was subjected to corona treatment so that the wetting coefficient was 60 dynes / cm, and then the semi-facing surface was treated in the same manner. Then, on one side, 8 of anti-fogging agents B-1 and B-2
A 0.5% by weight aqueous solution of a 0/20 (weight ratio) mixture was used to produce a spray coater of 4.8 g / m ² (anti-fogging agent 24 mg /
m ² ) After coating, it was passed through a hot air dryer at 110 ° C. for 10 seconds. Next, a 100-fold diluted aqueous solution of silicone oil S-2 (silicone oil concentration 0.3%) was applied to the half-faced surface of the antifogging agent by a spray coater at 3.5 g / m.
After applying ² (silicone oil 10.5 mg / m ² ), the product was passed through a hot air dryer at 110 ° C. for 20 seconds. The obtained sheet was wound with a winding tension of 20 to 25 kg / m to obtain a sheet roll. The sheet roll was aged at 23 ° C for 5 days. After aging, the transfer of the anti-fogging agent is not de confirmed, also silicone oils, average 3.7 mg / m ² transfer the antifogging agent coated surface, the silicone oil coated surface, average 6.8 mg / m ² coated That FTIR
(ATR method). The results of evaluating the physical properties of this sheet are shown in Table 1.

Example 9 The coating coefficient of the sheet antifogging agent-coated surface was 54 dyne / cm, the antifogging agent was a mixture of B-1 and B-3 at 65/35 (weight ratio), and the silicone oil was S-3. Then, a sheet roll was obtained in the same manner as in Example 8 except that the winding tension of the sheet was set to 15 to 20 kg / m. No transfer of the anti-fog agent was confirmed after aging, and the silicone oil was transferred on average 2.9 mg / m ² on the anti-fog agent coated surface, and the silicone oil coated surface was coated on average 7.6 mg / m ^2. This was confirmed by FTIR (ATR method). The results of evaluating the physical properties of this sheet are shown in Table 1.

[0065]

[Table 1]

Comparative Example 1 One side of the sheet prepared in Production Example 1 was corona-treated so that the wetting coefficient was 62 dynes / cm, and then silicone oil containing 0.5% by weight of the antifogging agent B-1 on this side. S-1
96-fold diluted aqueous solution (concentration of silicone oil 0.312
5 wt%) with a spray coater at 4 g / m ² (antifog agent 20 mg / m ² , silicone oil 12.5 mg /
m ² ) After coating, it was passed through a hot air dryer at 120 ° C. for 8 seconds. The obtained sheet was wound with a winding tension of 15 to 20 kg / m to obtain a sheet roll. 2 sheet rolls
After aging at 3 ° C. for 3 days, the sheet was rewound (winding tension at rewinding of 15 to 20 kg / m) and further aged at the same temperature for 7 days. After aging, the transfer of the anti-fog agent was not confirmed, and the silicone oil was coated on the surface on which the anti-fog agent was applied at an average of 6.7 mg / m ^2, and on the opposite surface was an average of 5.8 mg.
/ M ² transfer and that covers FTIR (ATR method)
Confirmed by The results of evaluating the physical properties of this sheet are shown in Table 2.

Comparative Example 2 A sheet roll was obtained in the same manner as in Example 1, except that the dilution ratio of silicone oil was 20 times (the amount of silicone oil applied was 60 mg / m ² ). No transfer of the anti-fog agent was confirmed after aging, and the silicone oil was transferred on the anti-fog agent-coated surface on average of 27.5 mg / m ² and the silicone oil-coated surface was covered on average of 32.5 mg / m ² . That F
It was confirmed by TIR (ATR method). The results of evaluating the physical properties of this sheet are shown in Table 2.

Comparative Example 3 A sheet roll was obtained in the same manner as in Example 8 except that the dilution ratio of silicone oil was 1200 times (the amount of silicone oil applied was 0.875 mg / m ² ). Aging transfer of Kobokumori agent can not be confirmed, silicone oil, transfer to anti-fogging agent coating surface is less than 0.05 mg / m ^2, the silicone oil coated surface, average 0.85 mg / m ² about The coating was confirmed by FTIR (ATR method). The results of evaluating the physical properties of this sheet are shown in Table 2.

Comparative Example 4 The concentration of the aqueous solution of antifogging agent was 0.075% by weight (3 mg of antifogging agent).
/ M ² ), and a sheet roll was obtained in the same manner as in Example 1. No transfer of the anti-fog agent was confirmed after aging, and the silicone oil was 5.0 mg on average on the anti-fog agent coated surface.
/ M ² coating, and the average of 7.
FTIR (ATR method) with 5 mg / m ² coating
Confirmed by The results of evaluating the physical properties of this sheet are shown in Table 2.

Comparative Example 5 The concentration of the antifogging agent aqueous solution was 1.75% by weight (70 mg of antifogging agent).
/ M ² ), and a sheet roll was obtained in the same manner as in Example 1. About 25% of the applied antifogging agent was transferred to the opposite surface, and the silicone oil had an average of 6.
1 mg / m ² was transferred, the silicone oil coated surface, that on average 6.4 mg / m ² coating FTIR (AT
R method). The results of evaluating the physical properties of this sheet are shown in Table 2. Note that this sheet was particularly sticky and had a reduced commercial value.

[0071]

[Table 2]

Examples 10 and 11 The wetting coefficient on both sides of the sheet was 54 dyne / cm (Example 1
0) and 48 dynes / cm (Example 11) except that corona treatment was performed to obtain a sheet roll. Table 3 shows the results of evaluating the transfer uniformity of the silicone oil of the obtained sheet.

Comparative Example 6 A sheet roll was obtained in the same manner as in Example 6 except that corona treatment was performed so that the wettability coefficient on both sides of the sheet was 43 dyne / cm. Table 3 shows the results of evaluating the transfer uniformity of the silicone oil of the obtained sheet.

Comparative Example 7 A sheet roll was obtained in the same manner as in Example 6 except that the two-step drying was not performed after the antifogging agent was applied (only the one-step drying was performed). Table 3 shows the results of evaluating the transfer uniformity of the silicone oil of the obtained sheet.

[0075]

[Table 3]

Example 12 A sheet roll was obtained in the same manner as in Example 1 except that the sheet prepared in Production Example 2 was used. The obtained sheet is
Transfer of anti-fogging agent is not de confirmed, also silicone oils, average 4.4 mg / m ² transfer the antifogging agent coated surface, that the silicone oil coating surface, are averaged 8.1 mg / m ² coating Was confirmed by FTIR (ATR method). The result of molding whitening evaluation of this sheet showed a linear numerical value of 80, and the other evaluation items were at the same level as the sheet of Example 1.

[0077]

EFFECTS OF THE INVENTION The sheet roll of the present invention is less likely to cause whitening during hot-plate pressure molding, and therefore gives a molded product having excellent transparency as compared with a molded product from a conventional sheet, and has anti-fog property and slipperiness. And excellent releasability. For this reason,
It can be suitably used as a styrene resin sheet roll for molding various packaging containers including food packaging containers.

[Brief description of drawings]

FIG. 1 is a schematic view of an example of the manufacturing method of the present invention by off-line coating.

[Explanation of symbols]

 1, sheet original fabric 2, styrene resin sheet 3, 4, corona treatment machine 5, 7, coater 6, 8, first stage dryer 9, second stage dryer 10, sheet roll after coating

Claims (3)

[Claims] 1. An antifogging styrene-based resin sheet coated with an antifogging agent and silicone oil on opposite sides with the coating amounts of (1) and (2) below is wound with a winding tension of 10 to 40 kg / m. A styrene-based resin sheet roll satisfying the following condition (3) when the sheet roll is rewound. (1) The coating amount of the antifogging agent is 5 to 50 mg / m ² . (2) The amount of silicone oil applied is 1 to 50 mg / m ^2.
It is. (3) A / (A + B) is 0 to 0.48. (However, A is the coating amount of silicone oil on the antifogging agent, and B is the coating amount of silicone oil on the opposite surface.) 2. The styrene resin sheet roll according to claim 1, wherein the antifogging agent is sucrose fatty acid ester and A / (A + B) is 0.1 to 0.35. 3. An anti-fogging styrene resin sheet coated with anti-fog agents and silicone oil on opposite sides with the coating amounts of (1) and (2) below was wound with a winding tension of 10 to 40 kg / m. A method for producing an anti-fog styrene resin sheet roll which is a styrene resin sheet roll and which satisfies the following (3) when the sheet roll is rewound, in the method, after forming the sheet, one side or both sides have a wetting coefficient of 45 to After corona treatment to 65 dynes / cm, apply anti-fog agent aqueous solution or silicone emulsion and dry, and then perform corona treatment on the remaining opposite surface in the same manner (omitted if already double-sided corona treatment) and then anti-fog agent aqueous solution. Alternatively, apply a silicone emulsion (different from the opposite side), dry it in two steps, and thoroughly dry it, and then wind it with a winding machine at a winding tension of 10-40 kg / m. A method for producing an antifogging styrene-based resin sheet roll, which comprises using a troll. (1) The coating amount of the antifogging agent is 5 to 50 mg / m ² . (2) The amount of silicone oil applied is 1 to 50 mg / m ^2.
It is. (3) A / (A + B) is 0 to 0.48. (However, A is the coating amount of silicone oil on the antifogging agent, and B is the coating amount of silicone oil on the opposite surface.)