JPS6136864B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a surface treatment method for imparting anti-fog properties, anti-blocking properties, slip properties, etc. to the surface of a stainless steel resin sheet. The present invention relates to an improved invention of a method for surface treatment of styrenic resin sheets, which is disclosed in the above publications. It has been known that it is necessary to perform a surface treatment on the surface of a styrene resin sheet to impart antifogging properties, antiblocking properties, slip properties, antistatic properties, etc. to the surface of the styrene resin sheet. In other words, when sheets are manufactured, transported, formed into containers, etc., and put into practical use, there are problems that occur in each process, such as sheets blocking each other, sheets tearing while running, etc.
This technology was developed to improve various process problems in which highly accurate and efficient molding cannot be performed, or containers become cloudy or dirty, which impairs the quality of containers and packaging products. It has been considered difficult to completely satisfy all of these problems. The reason is that in order to solve these various problems, it may be necessary to implement contradictory functions on the sheet, whereas the surface treatment method itself is Because it is a simple operation of depositing various treatment agent compositions on the sheet,
This is because the effectiveness of the composition of the processing agent used will greatly depend on the function. In other words, it is difficult for a single-component composition to have the function of resolving various problems at the same time, and if a multi-component composition is used, the functions of the components may cancel each other out, the components may separate, or completely different unexpected defects may occur. This comes from the fact that there are difficulties in deriving the title. As an excellent solution to the above problems, for example, the surface of the sheet is subjected to a corona discharge treatment to increase the surface tension of the sheet to 40 to 55 dyn/cm, and then an antifogging agent and silicone are applied. Japanese Patent Application Laid-Open No. 53-115781 proposed that oil be applied evenly
The method of the publication (hereinafter referred to as the method). as well as,
As the component composition of the treatment agent, a three-component mixed aqueous solution consisting of a certain sucrose fatty acid ester, silicone emulsion with a particle size of less than 1 μm, and undenatured polyvinyl alcohol is used, and this is uniformly applied to the sheet surface. Unexamined Japanese Patent Publication No. 1983 (1983) proposed to attach it to
- There is the method of Publication No. 166234 (hereinafter referred to as the method), etc. The first method is to combine different types of surface treatment methods to achieve both functions that tend to cause offset phenomena. The method is said to have the excellent effect of achieving the transparency and gloss of the sheet without impairing it, and in short, the method uses the binder function of unmodified polyvinyl alcohol to achieve the same properties as the above method. maintain function,
It achieves the same or better effect, and also has the advantage of not necessarily requiring corona discharge treatment. However, these conventional methods have not been able to keep up with the recent diversification of practical applications and the increasing quality required as technological standards have improved, and many drawbacks have been discovered. That is, in the method (2), for example, the anti-fog durability is short (about 30 minutes), the anti-fog property is impaired when used for deep drawing, and the anti-static effect is insufficient, so the molding workpiece cannot be used. Problems arise, such as the adhesion of foreign matter being noticeable and the management of it being time-consuming.
and unsuitable for resin recovery and use. In addition, uniform application of the treatment agent is required to achieve design quality including appearance quality, but it is difficult to maintain the treatment agent in a stable state, and its management is difficult. Problems such as excessive costs have arisen. The present invention is an improvement method made in view of the current situation, and its first purpose is to provide properties that could not be achieved with the above conventional methods, that is, in particular, to provide long-lasting anti-fog properties. The purpose of the present invention is to provide a method for imparting long-lasting properties, anti-fogging properties, and deep drawing suitability while also having antistatic properties. The third purpose is to provide a method that achieves the collection suitability and ease of treatment agent management without impairing it at all.
In addition to the second object, it is an object of the present invention to provide a sheet that is suitable for fields where a high degree of slipperiness is required. The above-mentioned objects 1 to 3 are achieved by methods 1 and 2 of the present invention, namely, 1. One surface of a styrene resin sheet is previously subjected to a corona discharge treatment to increase the surface tension of the sheet, and then a surface treatment agent is applied to the sheet. In the surface treatment method for imparting anti-fog properties, anti-blocking properties, etc. to the surface of the sheet, () the surface tension of the sheet is set in the range of 50 to 60 dyn/cm by electric discharge treatment; (A) The proportion of fatty acid residues with carbon number 12 or less in the fatty acid residue composition is
70% or more, the ratio of lauric acid residues in the fatty acid residues is 65% or more, and the monoester content in the ester composition is 70% or more, and (B) coconut oil fatty acid diethanolamine. (2) The coating amount should be such that the above (A) component is applied per 1 square meter of sheet.
An improved styrene system characterized by satisfying the above (), (), and () of adhering almost uniformly so that component (B) is in the range of 10 to 25 mg and 1.5 to 4 mg, respectively. Surface treatment method for resin sheets. 2. Perform corona discharge treatment on one surface of the styrene resin sheet in advance to increase the surface tension of the sheet, and then apply a surface treatment agent thereon to impart anti-fog properties, anti-blocking properties, etc. to the surface of the sheet. In the surface treatment method, () the surface tension of the sheet is set in the range of 50 to 60 dyncm by discharge treatment;
(A) The proportion of fatty acid residues with carbon number of 12 or less in the fatty acid residue composition is 70% or more, and the proportion of lauric acid residues in the fatty acid residues is
Select and use a combination of sucrose fatty acid ester and (B) coconut oil fatty acid diethanolamide that satisfy the relationship that the monoester content in the ester composition is 65% or more and the monoester content in the ester composition is 70% or more; , the above (A) component per square meter of sheet is 10~
25mg, and (B) component is deposited almost uniformly in the range of 1.5 to 4mg (),
(), (), and on the other side of the sheet, apply a silicone oil emulsion almost uniformly so that the amount of silicone oil component adhered is in the range of 8 to 40mg per square meter of the sheet. This can be easily achieved by using an improved method for surface treatment of styrenic resin sheets characterized by the following. Hereinafter, before explaining the contents of the present invention in detail, first the relationship between the first invention and the second invention of the present invention will be clarified. The second invention of the present invention is the same as the first invention in the essential parts of the structure of the invention, and has substantially the same effects. However, the difference between the two is that the second invention has the additional feature that a silicone emulsion is applied to the other side of the sheet compared to the first invention, so the effect is correspondingly greater. Therefore, in this specification, the main parts common to the first invention and the second invention will be explained in detail, and then the different parts of the second invention will be explained. Hereinafter, the common main parts of the present invention will be explained in detail with reference to the result table and the like. First, we will introduce the features of the method of the present invention, that is, examples of the characteristics of the present invention that could not be achieved with the prior art. Table 5 shows the suitability for deep drawing for anti-fog properties.
A total of 4 sheets, including the current commercially available sheets (manufactured by Company X, Company Y, and Company Z) and the sheet of Example 1 of JP-A-53-115781.
It is a result table showing a comparison between a standard sheet and a sheet according to the method of the present invention.

[Table] According to the results in Table 5, the deep drawing suitability for anti-fog properties is at most 0.1 or less in the drawing ratio (drawing depth/aperture diameter) of the conventional technology, whereas the deep drawing suitability obtained with the present invention is The sheet shows the fact that a large improvement effect of up to 0.6 (ie, 6 times) has occurred. This effect is due to the fact that molded containers that can guarantee anti-fog properties are limited to containers with a specific shape that sacrifices resin recovery suitability or have a small drawing ratio, or that individual containers are sprayed after molding to prevent fogging. This can be said to be an extremely beneficial advantage, since it can significantly improve the situation in which people had to re-assign gender. Table 6 is a results table showing a comparison of the same representative sheets as in Table 5 regarding anti-fog durability.

[Table] The results in Table 6 also show that the sheet obtained according to the present invention has an anti-fogging effect that is well 12 times longer than that of the conventional product. This effect is directly related to the lifespan of the product value, as when the container containing the contents is displayed in a store, the container becomes cloudy due to the water vapor generated from the contents, making it impossible to see through the contents. ,
This can be said to have very direct practical advantages. The common important requirements of the present invention that produce the advantages represented in Tables 5 and 6 above are: () The surface tension of the sheet due to electric discharge treatment is
60 dyn/cm () The surface treatment agent must contain (A) The proportion of fatty acid residues with carbon number 12 or less in the fatty acid residue composition is 70% or more, and the proportion of lauric acid residues in the fatty acid residues is 70% or more. The proportion of monoester is 65% or more, and the monoester content in the ester composition is 70%.
Select and use a combination of sucrose fatty acid ester that satisfies the above relationship and (B) coconut oil fatty diethanolamide;
This method is a combination of (), (), and () above, in which component (A) is deposited almost uniformly in a range of 10 to 25 mg, and component (B) is deposited in a range of 1.5 to 4 mg. The reason why this combination is necessary is that the three factors are integrated, so it is difficult to analyze the effects by stratifying them into individual factors, but for convenience, I will explain this by stratifying it below. . First, the reason why () is necessary is shown in Table 2. In other words, it is intended to satisfy the anti-fogging durability by combining initial anti-fogging property and blocking resistance, and the surface tension of the sheet is a large value exceeding 60 dyn/cm, or 50 dyn/cm.
This is because when the value is set to a value smaller than cm, a phenomenon occurs in which initial antifogging properties, antifogging durability, or blocking resistance are no longer satisfied.

[Table] This phenomenon is a unique phenomenon that was first investigated in relation to the processing agent described in component (), and it is a phenomenon within an extremely narrow range in which sheet surface treatment methods using different methods can synergize the functions of each method. . From the perspective of stabilizing and balancing the properties of the sheet obtained, the surface tension of the sheet should be set at 54 to 58 dyn/
It is more effective to control within a cm range. Next, the reason for choosing the combination of sucrose fatty acid ester and coconut oil fatty acid diethanolamide in () above is that even though they are the same substances known as antifogging agents and surface treatment agents, other This is because if it is combined with other materials or other materials, it will not be possible to achieve a high level of antistatic properties, antifogging durability, appearance quality, resin recovery suitability, deep drawing suitability for antifogging properties, etc. . The current situation is shown in Table 3.
1. It is shown in Table 3-2.

【table】

【table】

[Table] Particularly, the processing agent of the present invention has a high antistatic property, and has the advantage that it is easy to adjust the processing agent, probably due to its excellent compatibility, and to manage the processing agent because it is highly stable over time. This combination of two-component compositions is normally used as a mixed aqueous solution in suitable proportions, but the treatment agent of the present invention produces the same effect as mixed adhesion even when each individual aqueous solution is applied over and over again. Therefore, there is an advantage that the attachment means can be used differently depending on the process. However, the sucrose fatty acid ester that can be used in the present invention must satisfy the condition (A) above. The reason for this is shown in Figures 1 to 3. In other words, Figures 1 to 3 show the relationship between the effects of the components in the sucrose fatty acid ester. The relationship between the proportion [%] of fatty acid residues with a carbon number of 12 or more and the resulting sheet HAZE difference (△H), Figure 2 shows the proportion [%] of lauric acid residues in the fatty acid residue composition as above. Figure 3 shows the relationship between the monoester content [%] in the ester composition of sucrose fatty acid ester and the difference in HAZE of the obtained sheet (△H). It shows the relationship between each. According to the results shown in Figures 1 to 3, from the viewpoint of making the treatment agent of the present invention exhibit the function of imparting antifogging durability without impairing the appearance of the sheet, fatty acid residues with carbon numbers of 12 or less in the fatty acid residues are The proportion of groups
70% or more (Figure 1), the proportion of lauric acid residues is 65
% or more (Figure 2) and the monoester content in the ester composition is 70% or more (Figure 3). By the way, sucrose fatty acid esters are coconut oil,
Natural vegetable oils such as sesame oil and palm kernel oil, animal oils such as beef tallow and pork fat, and processed oils that are refined from these oils.
Because chemically synthesized fatty acids are used as raw materials, various types of fatty acids may be mixed together, and their component ratios may vary, making it uncertain, and during esterification, esters with different degrees of esterification may be produced. Therefore, even if they are conceptually expressed as the same sucrose ester, their content properties are considered to be diverse. Therefore, for use in the present invention, it is necessary to restrict or analyze the raw fatty acids in advance and carefully select the component composition. Next, the reason why () is necessary is the above (),
Even if all the conditions in () are met, (A) and (B)
If the amount of each component attached does not satisfy a certain range, the target function will not occur. The current relationships are shown in Table 4. In addition, these adhering components are usually made into a relatively dilute aqueous solution containing a mixture of (A) and (B), and are applied to the sheet using a roll coating method, followed by drying to easily form a nearly homogeneous film. do.

[Table] That is, according to Table 4, from the standpoint of achieving both anti-fog durability and anti-static properties without impairing the appearance quality, the amount of component (A) should be 10 to 25 mg, and the amount of component (B) should be 1.5 to 25 mg. 4mg,
It is absolutely necessary that the (A) component be adhered to 15 to 20
It can be seen that it is preferable to set the combined amount of the component (B) in a range of 2 to 3 mg. Since the above-mentioned amount of adhesion is per square meter of sheet, it is naturally more likely that the amount of adhesion will be more evenly distributed. Fortunately, the treatment agent of combination (A) and (B) has excellent spreadability on the sheet due to the surface tension of the sheet, so there is no need to choose a particular attachment method.
Another advantage is that it can be uniformly distributed by a known coating method suitable for the process employed. Next, the second invention will be described. As mentioned above, the important parts of the second invention are common to the first invention. Therefore, regarding the different parts, the second invention is different from the first invention in that a silicone emulsion is attached to the other surface of the sheet. This necessity requires that the resulting sheet be, for example, shown in FIG.
When used in applications where stacked containers are cut out as shown in (b), the ease with which individual containers can be taken out will determine the productivity of the next practical process. This is to give the sheet a high level of slipperiness that satisfies the requirements (in this book, evaluation is based on molded product releasability). This high level of slipperiness is delicate and necessary for specific applications, and is not necessarily correlated with blocking resistance. Therefore, when this is required of the sheet obtained in the first invention, there may be some deficiencies, so the second invention is designed to compensate for this. However, in this case, the silicone emulsion should be attached to the surface other than the surface treated with the above treatment agents (A) and (B), and should not be mixed with the treatment agents (A) and (B). must not. This is because the stability of the treatment agents (A) and (B) will be significantly deteriorated, and as a result, some or most of the target surface properties of the sheet will be impaired. The appropriate amount of silicone emulsion to be applied is 8 to 40 mg of pure silicone oil per square meter of sheet. The results in Table 7 demonstrate that relationship. In this way, even after the treated surfaces of a sheet treated with different types of treatment agents, if the sheet is stored in a rolled layer, for example,
For example, a small amount of silicon components from the other surface may transfer to the treated surfaces (A) and (B). However, the sheet in this state does not impair the original properties of the sheet of the second invention at all, and is uniformly different from a sheet coated with silicon mixed in components (A) and (B).

[Table] The styrenic resins used in the present invention include general purpose polystyrene (GPPS), rubber reinforced polystyrene (HI, PS), styrene-butadiene copolymer, and AS.
These are resins such as resins and mixtures thereof. In addition, the styrenic resin sheet referred to in the present invention is a sheet formed by film-forming and biaxially stretching the above-mentioned styrene resin by a method such as a T-die method or an inflation method, and the thickness thereof is 0.09～1mm
refers to something. Surface tension of the sheet in the present invention (dyn/cm)
refers to the value determined in accordance with ASTM D 2578.
In this case, the index reagent used was a reagent containing special grade ethanol and distilled water at a pitch of 2 dyn/cm between 30 and 70 dyn/cm. The evaluation criteria for each evaluation item in Examples and Comparative Examples are as follows. (1) Initial antifogging properties and antifogging durability The sheet is formed into a cup-shaped container with an opening of 80 mmφ, a drawing depth of 30 mm, and a flange width of 3 mm so that the treated surface is the inner surface, and the container is soaked in water at 20℃. Polypropylene cylindrical container (opening 80mmφ, depth
50 mm, flange width 5 mm) with the inner surface facing down, and the flange portion was fixed with cellophane adhesive tape, then placed in a refrigerator maintained at a temperature of 5° C., and visually evaluated after aging. Initial anti-fog properties are shown after 5 minutes, and anti-fog durability is shown after 48 hours.

[Table] (2) Blocking resistance Two sheets with surface treatment and coating drying
Overlap the treated and coated surfaces so that they touch each other,
After pressing for 1 minute in an atmosphere at 40°C, the two sheets were peeled off and the pressing pressure at which white marks started to appear due to adhesion was examined. (The pressure was increased to 10 kg/ ^cm2 pitch.)

[Table] (3) Appearance quality of molded product A sheet is molded into a tray-shaped container measuring 200 mm long x 130 mm wide x 10 mm deep and has a 5 mm wide flange at the opening. ―
The cloudiness H measured by 1003 and the appearance observed with the naked eye are evaluated, and if either of them is evaluated low,
Ranked on the low side.

[Table] (4) Resin recovery suitability After cutting the treated coated sheet into 5mm square pieces,
Transfer 90g of that to Labo Plastomill 100 manufactured by Toyo Seiki Co., Ltd.
After kneading at 220℃ for 20 minutes using a twin-screw kneader, the thickness was
A casting plate measuring 2.5mm, 50mm in length, and 50mm in width was molded. After cooling this to room temperature, JIS-K-
Yellowness YI was measured using 7103. Next, the degree of yellowing ΔYI was determined from YI ₀ , which was measured in the same manner as above using an untreated sheet as a blank value, and evaluated as ΔYI=YI−YI ₀ .

[Table] (5) Deep drawing antifogging properties Form the sheet into a deep drawn cup-shaped container with an opening of 80 mmφ, drawing depth of 50 mm, and flange width of 3 mm so that the treated surface is the inner surface, and store this container at 20℃. of water
Polypropylene cylindrical container containing 150ml (opening
80mmφ, depth 50mm, flange width 5mm) with the inner surface facing down, and after fixing the flange part with cellophane adhesive tape, put it in a refrigerator kept at 5℃, and check the condition after 48 hours. Visually judge.

[Table] (6) Antistatic property The treated surface of the sheet was evaluated by measuring the surface resistance value R _S [Ω] according to ASTM-D-257.

[Table] (7) Sheet HAZE difference △H Stack 10 coated sheets and apply ASTM-D
-1003, the difference △H [%] = H - H ₀ between the measured haze H and H ₀ similarly measured by stacking 10 uncoated sheets was determined. (8) Anti-fogging duration The anti-fogging duration was tested in the same manner as in (1), and the time T [time] at which a so-called cloudy state due to micro water droplets began to appear was measured. (9) Appearance quality of the sheet The sheet is evaluated by two factors: the haze H measured by ASTM-D-1003 and the appearance observed with the naked eye. Ranked.

[Table] (10) Molded product peelability (slip property) This will be explained with reference to Figure 4 A and B. sheet
A rectangular container, 170 mm long x 110 mm wide x 40 mm deep, with a 5 mm wide flange at the opening is used. Stack 20 square containers 1 with the opening facing up, place a 5 kg load 2 on the inside of the top container,
At that time, the thickness H ₁ [mm] of the overlapping portion was measured. Next, the load 2 was removed, and after 1 minute, the thickness H ₂ [mm] of the overlapped portion was measured again, and the recovery rate R was determined using the following formula. R=H ₂ −H ₁ /H ₁ ×100 [%]

【table】

[Conditions for fixed common parts]

(a) Coronar discharge treatment conditions: The target surface tension of the sheet is 54 dyn/cm. (b) Type of treatment agent; Sucrose fatty acid ester [changed based on the following hypothesis] Coconut oil fatty acid diethanolamide (B) (c) Component composition of treatment agent Aqueous solution of 4.5% by weight and 0.6% by weight (d) Adhesion method : Adhesion to the corona-treated surface by roll coating method (e) Amount of adhesion (per square meter of sheet) 15mg, 2mg, target [Changes based on hypothesis] ◎First hypothesis; Fatty acid residue of sucrose fatty acid ester The proportion of fatty acid residues having 12 carbon atoms or less in the composition influences the appearance of the resulting sheet. 〇 Sucrose fatty acid ester used in the experiment; Table 1 Prototype code, 5 levels of a, b, c, and dl 〇 Evaluation items; Sheet HAZE difference (△H) described in the text 〇 Display of result analysis; Figure 1 ◎ Hypothesis 2: The proportion of lauric acid residues in the fatty acid residue composition of the sucrose fatty acid ester influences the antifogging effect of the resulting sheet. 〇Sucrose fatty acid esters to be used in experiments, Table 1 Prototype code d, e, f, g, m (5 levels) 〇Evaluation items; Anti-fogging duration as described in the text 〇Display of result analysis; Figure 2, ◎Third hypothesis: The monoester content in the ester composition of the sucrose fatty acid ester is determined by the appearance of the resulting sheet. Affects dignity. 〇Sucrose fatty acid ester used in the experiment; Table 1: 5 levels of prototype code: g, h, i, j, k (in each case, the proportion of fatty acid residues with carbon numbers of 12 or less is 70
% or more and lauric acid residues of 65% or more) 〇Evaluation items; Sheet HAZE difference (△H) described in the text 〇Result analysis display; Figure 3 The results in Figures 1 to 3 are shown in the book. This proves the correctness of the first to third hypotheses regarding the invention, etc. In other words, the results shown in Figure 1 demonstrate that a sucrose fatty acid ester capable of achieving the purpose of the present invention needs to have a fatty acid residue composition with a carbon number of 12 or less in a proportion of 7% or more. It shows. The results shown in Figure 2 indicate that even if the sucrose fatty acid ester satisfies the desirable conditions shown in Figure 1, the proportion of lauric acid residues in the fatty acid residue composition must be 65% or more in order to achieve the purpose of the present invention. It shows the need to be something. Furthermore, the results shown in Figure 3 indicate that even if the sucrose fatty acid ester satisfies the desirable conditions shown in Figures 1 and 2 above, the monoester content in the ester composition is insufficient to achieve the objectives of the present invention. This indicates that the content must be 70% or more of sucrose fatty acid ester. Taking all the above into account, the sucrose fatty acid ester (A) used in the method of the present invention has the following properties: 〇 The proportion of fatty acid residues having 12 carbon atoms or less in the fatty acid residue composition is 70% or more, and 〇 Fatty acid residue composition The proportion of lauric acid residues in the composition is 65% or more, and the monoester content in the ester composition is
70% or more is a sucrose fatty acid ester that satisfies the following conditions. Comparative Example 5 The following rolls of biaxially oriented polystyrene antifogging specification sheets from various companies were obtained as commercial products. Manufacturer classification Brand (thickness x width x roll length) Manufactured by Company X 0.21mm × 1040mm × 600M Manufactured by Company Y 0.21mm × 1020mm × 500M Manufactured by Company Z 0.21mm × 980mm × 600M The method of the present invention was applied to these three types of commercially available sheets. A representative sheet (experiment No. 29) obtained in
A sheet (thickness 0.21 mm) obtained by redefining the processing conditions of Example 1 of Publication No. 115781 was added, and the antifogging performance of each was evaluated comparatively, and the results are shown in Tables 5 and 6. Summarized. In other words, the evaluation in Table 5 is based on molding each sheet into a molded product with a drawing ratio (depth dimension/opening diameter dimension) that increases step by step in steps of 0.05, and each molded product passing the anti-fog test described in the text. The anti-fogging property shown after 24 hours under the conditions is expressed using a scale symbol, and the degree of deep drawing withstood is compared and evaluated. On the other hand, Table 6 shows the anti-fog condition that changes over time in the anti-fog test for molded products of the same sheet with an aperture ratio of approximately 4, using scale symbols in the text, and compares and evaluates the anti-fog durability over time. be. According to the results in Table 5, the sheet (No. 29) obtained by the method of the present invention showed excellent deep drawing resistance compared to any conventional product, and had about 6 times the deep drawing performance. It turns out that. Also, according to the results in Table 6, the sheet (No. 29) obtained by the method of the present invention has a 12
It can be seen that the anti-fog durability is twice as long. The sheet of the present invention having such practical characteristics has hitherto been in demand as a market requirement but has not been able to satisfy it, so it is a sheet that will make a significant contribution to the industry, and this book can achieve this. It can be said that the method of the invention (first invention) is an excellent improved invention. Example Comparative Example 6 After producing the sheet of Example/Comparative Example 1 No. 3,
On the other side of the sheet opposite to the treated side, apply a silicone emulsion [Shin-Etsu Silicone KM787B, Shin-Etsu Chemical Co., Ltd., 10 times diluted aqueous solution] by a roll coating method, and apply the silicone oil adhesion amount as shown in Table 7. Sheets (Experiment Nos. 35 to 44) were prepared. The resulting sheets Nos. 35 to 44 were evaluated for molded product releasability and sheet appearance using the methods described in the text, and the results are shown in Table 7. According to the results in Table 7, products with a silicone oil adhesion amount of less than 8 mg/cm ² (i.e., products of the first invention) are required to have a high level of molded product releasability (equivalent to slipperiness). When applying silicone oil 8 to 40% on the other side of the sheet, it shows unsatisfactory results.
It can be seen that those coated with mg/m ² (Nos. 35 to 38) satisfy molded product releasability. On the other hand, when the amount of silicone oil applied exceeds 40 mg/m ² , the appearance of the sheet is impaired. From the viewpoint of maintaining a high level of molded product releasability and sheet appearance, it is found that it is desirable to maintain the amount of silicone oil applied within the range of 15 to 30 mg/m ² . According to experiments conducted by the present inventors, pure silicone oil was added to the processing agent solution from which sheet No. 3 was obtained.
When 4.5% by weight was mixed, in addition to deteriorating the appearance of the sheet, as the coating experiment continued, it was observed that the anti-fog durability, deep drawing anti-fog properties, etc. also deteriorated. By having the above-described structure, the present invention provides long-term anti-fog durability and anti-fog properties without impairing the appearance quality of the sheet (molded product), the recovery suitability of the resin, the ease of managing the processing agent, etc. Cloudy deep drawing suitability, chargeability and, if necessary, molded product peelability (slip properties)
can be achieved at a high level. Although this effect has recently been strongly desired as a practical market requirement, it has not been possible to achieve with conventional techniques, so the invention is useful to industry as a highly practical improved technique.

[Brief explanation of the drawing]

Figures 1 to 3 are graphs showing the relationship between the components of sucrose fatty acid ester and the performance of the sheet (molded product) obtained by coating, and Figure 4 (a) is a square container with a load placed on it. , FIG. 4(b) is a perspective view of the rectangular container with the load removed. 1...Square container, 2...Load, _H1 , _H2 ...Thickness of overlapped part [mm].

Claims (1)

[Claims] 1. One surface of the styrene resin sheet is previously subjected to a corona discharge treatment to increase the surface tension of the sheet, and a surface treatment agent is adhered thereon to give the surface of the sheet antifogging and resistant properties. In the surface treatment method for imparting blocking properties, etc., () the surface tension of the sheet by discharge treatment is set in the range of 50 to 60 dyn/cm, () the surface treatment agent includes (A) carbon that accounts for the fatty acid residue composition; The proportion of fatty acid residues with number 12 or less is 70% or more, and the proportion of lauric acid residues in fatty acid residues is
Select and use a combination of sucrose fatty acid ester and (B) coconut oil fatty acid diethanolamide that satisfy the relationship that the monoester content in the ester composition is 65% or more and the monoester content in the ester composition is 70% or more; The above (A) component is 10 to 25 per square meter of sheet.
(2) above (), where the amount of component (B) is approximately uniformly deposited in the range of 1.5 to 4 mg.
Improved surface treatment method for styrenic resin sheet characterized by satisfying (), () 2 A corona discharge treatment is performed on one surface of the styrenic resin sheet in advance to increase the surface tension of the sheet, and then In a surface treatment method in which a surface treatment agent is attached to the surface of the sheet to impart anti-fogging properties, anti-blocking properties, etc. to the surface of the sheet, () the surface tension of the sheet is set in the range of 50 to 60 dyn/cm by electric discharge treatment; () The surface treatment agent contains (A) a proportion of fatty acid residues with carbon numbers of 12 or less in the fatty acid residue composition of 70% or more, and a proportion of lauric acid residues in the fatty acid residue composition.
Select and use a combination of sucrose fatty acid ester and (B) coconut oil fatty acid diethanolamide that satisfy the relationship that the monoester content in the ester composition is 65% or more and the monoester content in the ester composition is 70% or more; , the above (A) component per square meter of sheet is 10~
25mg, and (B) component should be deposited almost uniformly in the range of 1.5 to 4mg (),
(), (), and on the other side of the sheet, apply a silicone oil emulsion almost uniformly so that the amount of silicone oil component adhered is in the range of 8 to 40mg per square meter of the sheet. An improved method for surface treatment of styrenic resin sheets, characterized by: