JP2008212793A - Method of drying solvent-containing resin composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of drying a solvent-containing resin composition by which the solvent-containing resin composition containing a solvent and applied on a base material is dried in a short time and the deformation or the deterioration of the base material is suppressed and the quality of the resin composition after dried is improved. <P>SOLUTION: The method of drying the solvent-containing resin composition 3 containing the solvent applied on one surface 2a of the base material 2 is provided with a first drying step for making the temperature in the surrounds of the base material side higher than that in the surrounds of the solvent-containing resin composition side and a second drying step for making the temperature in the surroundings of the solvent-containing resin composition side higher than that in the surroundings of the base material side after the first drying step. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for drying a solvent-containing resin composition containing a solvent applied to one side of a substrate, and more specifically, the ambient temperature on the substrate side and the ambient temperature on the solvent-containing resin composition side, The present invention relates to a method for drying a solvent-containing resin composition that varies depending on the drying time.

  A laminate in which a resin composition layer is formed on one side of a substrate is known. As the substrate, for example, a plate-like body or a molded product or a film or sheet made of wood, metal, resin, ceramic or the like is used. The resin composition layer contains, for example, an adhesive, a pressure-sensitive adhesive, a colorant, and the like.

  When obtaining the said laminated body, after apply | coating the solvent containing resin composition containing a solvent on a base material, it dries and the removal of the solvent is performed. In drying, for example, in a furnace surrounded by a metal plate, earth, or the like, a drying method in which air at a constant temperature is blown over the solvent-containing resin composition on the base material is widely adopted. .

  In the above drying method, for example, if drying is performed at a temperature exceeding the heat resistance temperature of the substrate, the substrate may be deformed or deteriorated. On the other hand, if the drying temperature is too low, the drying time becomes longer.

Therefore, in order to prevent deformation and alteration of the base material and shorten the drying time, the following Patent Document 1 includes a surface opposite to the printed or coated surface, that is, a surface on the base material side while cooling. There is disclosed a method of drying by spraying warm / hot air on a printed or coated surface. As a printing or coating material, a solvent-containing resin composition containing a solvent is widely used.
JP 2001-12849 A

  In Patent Document 1, since the surface opposite to the printed or coated surface, that is, the surface on the base material side is dried while being cooled, deformation of the base material can be suppressed.

  However, in patent document 1, the wind of comparatively high temperature was sprayed on the printed or coated surface, ie, a solvent containing resin composition, from the dry initial stage. In this case, since the temperature of the solvent-containing resin composition suddenly increases in the initial stage of drying, only the surface of the solvent-containing resin composition may be dried, and a solidified skin layer may be formed on the surface of the resin composition. .

  When the skin layer is formed, foaming or bubble entrainment may occur in the dried resin composition, or pinholes may be formed. Therefore, unevenness may occur on the surface of the resin composition, or the transparency of the resin composition may be reduced.

  In addition, the skin layer hinders evaporation of the solvent inside the resin composition, and it may take a long time to dry or the solvent may not be removed sufficiently.

  The object of the present invention is to allow a solvent-containing resin composition containing a solvent applied on a substrate to be dried in a short time and to suppress deformation and alteration of the substrate in view of the above-described state of the prior art. And it is providing the drying method of the solvent containing resin composition which can improve the quality of the resin composition after drying.

  1st invention is a drying method of the solvent containing resin composition containing the solvent apply | coated to the one surface of a base material, Comprising: Ambient temperature by the side of a base material is made higher than the ambient temperature by the side of a solvent containing resin composition A first drying step, and a second drying step for making the ambient temperature on the solvent-containing resin composition side higher than the ambient temperature on the substrate side after the first drying step. To do.

  2nd invention is the drying method of the solvent containing resin composition which blows and dries on the solvent containing resin composition containing the solvent apply | coated to the one surface of the base material, Comprising: The temperature of the wind sprayed on a base material Is higher than the temperature of the wind sprayed onto the solvent-containing resin composition, and after the first drying step, the temperature of the wind sprayed onto the solvent-containing resin composition is adjusted to And a second drying step that is higher than the temperature.

  In a specific aspect of the solvent-containing resin composition of the present invention, the first drying step is performed in the early stage of drying, and the second drying step is performed in the late stage of drying.

  In the drying method of the solvent-containing resin composition according to the first aspect of the present invention, since the first drying step for making the ambient temperature on the substrate side higher than the ambient temperature on the solvent-containing resin composition side is provided, It is possible to prevent a solidified skin layer from being formed on the surface of the resin composition. Therefore, generation | occurrence | production of foaming, bubble entrainment, etc. can be suppressed in the resin composition after drying. Therefore, the quality of the resin composition after drying can be improved.

  Further, since the second drying step is provided after the first drying step, the ambient temperature on the solvent-containing resin composition side is higher than the ambient temperature on the substrate side, the solvent can be sufficiently removed in a short time. Can be removed. Moreover, since the time for which the substrate is exposed to high temperatures can be made relatively short, deformation of the substrate can be suppressed.

  In the drying method of the solvent-containing resin composition according to the second invention, since the first drying step of making the temperature of the wind sprayed on the substrate higher than the temperature of the wind sprayed on the solvent-containing resin composition, The formation of a solidified skin layer on the surface of the solvent-containing resin composition can be prevented. Therefore, generation | occurrence | production of foaming, bubble entrainment, etc. can be suppressed in the resin composition after drying. Therefore, the quality of the resin composition after drying can be improved.

  Furthermore, since the second drying step is performed after the first drying step, the temperature of the wind sprayed onto the solvent-containing resin composition is made higher than the temperature of the wind sprayed onto the base material. Can be sufficiently removed. Moreover, since the time for which the substrate is exposed to high temperatures can be made relatively short, deformation of the substrate can be suppressed.

  When the first drying step is performed in the early stage of drying and the second drying step is performed in the late stage of drying, the drying time can be further shortened. Moreover, the quality of the resin composition after drying can be further enhanced.

  Details of the present invention will be described below.

  A method for drying a solvent-containing resin composition according to an embodiment of the present invention will be described below with reference to FIG.

  In FIG. 1, the internal structure of the drying apparatus used with the drying method of the solvent containing resin composition which concerns on one Embodiment of this invention is shown with the schematic block diagram.

  As shown in FIG. 1, when drying, first, a laminate 1 of a base material 2 and a solvent-containing resin composition 3 containing a solvent applied to the upper surface 2 a of the base material 2 is prepared. The laminate 1 is disposed in the drying device 11. Here, the laminated body 1 is arrange | positioned so that the base material 2 may become a downward side and the solvent containing resin composition 3 may become an upper side.

  Although it does not specifically limit as the base material 2, For example, the plate-shaped body, molded product, film, sheet | seat etc. which consist of wood, a metal, resin, a ceramic, etc. are mentioned.

Although it does not specifically limit as resin used for the solvent containing resin composition 3, For example, an acrylic polymer, a polyurethane, succinic acid, a rosin, a coloring agent etc. are mentioned.
Although it does not specifically limit as a solvent used for the solvent containing resin composition 3, For example, ethyl acetate, toluene, xylene, alcohol, etc. are mentioned.

  In the drying apparatus 11, a nozzle 12 having an opening hole 12 a for blowing air A onto the solvent-containing resin composition 3 is provided above the solvent-containing resin composition 3. On the other hand, a nozzle 13 having an opening hole 13 a for blowing the wind B onto the base material 2 is provided below the base material 2. The drying device 11 is configured to blow out wind at a predetermined temperature at a predetermined wind speed from the opening holes 12a and 13a of the nozzles 12 and 13.

  At the time of drying, the temperature of the wind B sprayed on the base material 2 is set higher than the temperature of the wind A sprayed on the solvent-containing resin composition 3, and drying is performed. Thereby, the ambient temperature by the side of the base material 2 can be made higher than the ambient temperature by the side of the solvent containing resin composition 3 (1st drying process).

  The first drying step is preferably performed at the initial stage of drying. More preferably, the first drying step is performed immediately after the solvent-containing resin composition is applied until the temperature of the wind A is set to a temperature exceeding the boiling point of the solvent in the solvent-containing resin composition.

  In the first drying step, when the solvent contained in the solvent-containing resin composition 3 is ethyl acetate (boiling point 77.15 ° C.), for example, the temperature of the wind A is 50 to 77 ° C., and the temperature of the wind B May be set to 78 ° C. or higher. Specifically, for example, the temperature of the wind A may be 60 ° C., and the temperature of the wind B may be 90 ° C.

  In the first drying step, it is preferable that the temperature of the wind B sprayed on the substrate 2 and the ambient temperature on the substrate 2 side are lower than the heat-resistant temperature of the substrate 2. In addition, the heat-resistant temperature of a base material means the maximum temperature which does not produce a deformation | transformation and a quality change of a base material.

  For example, when the base material 2 includes polyethylene, the heat resistance temperature of the base material 2 is about 124 ° C., but the temperature of the wind B sprayed on the base material 2 and the ambient temperature on the base material 2 side are 124 ° C. or less. It is preferable that the temperature is 120 ° C. or lower.

  By the way, the diffusion coefficient which becomes an index of the evaporation of the solvent in the solvent-containing resin composition largely depends on the temperature and the solvent concentration. The higher the temperature and solvent concentration, the greater the diffusion coefficient. That is, if there is a temperature difference, a difference also occurs in the diffusion coefficient. Therefore, when there is a temperature difference in the solvent-containing resin composition, for example, when there is a temperature difference in the thickness direction, a concentration difference (concentration gradient) is generated. Generally, since the diffusion equation is expressed by the product of the diffusion coefficient and the concentration gradient, the solvent diffusion rate can be increased by generating a temperature gradient in the thickness direction of the solvent-containing resin composition.

  In the first drying step, the solvent in the vicinity of the surface of the solvent-containing resin composition 3 is relatively difficult to diffuse, whereas the solvent inside the solvent-containing resin composition 3 is promoted to diffuse. Therefore, it is possible to prevent the surface of the solvent-containing resin composition 3 from drying and forming a solidified skin layer on the surface.

  Moreover, since a temperature difference arises in the thickness direction of the solvent-containing resin composition 3, the diffusion rate of the solvent can be increased and the solvent can be efficiently evaporated.

  After the first drying step, the temperature of the wind A sprayed on the solvent-containing resin composition 3 is set higher than the temperature of the wind B sprayed on the substrate 2, and drying is performed. Thereby, the ambient temperature on the solvent-containing resin composition 3 side can be made higher than the ambient temperature on the substrate 2 side (second drying step).

  The second drying step is preferably performed in the late drying stage. More preferably, the second drying step is performed after the temperature of the wind A is set to a temperature exceeding the boiling point of the solvent in the solvent-containing resin composition, and then the drying is completed.

  In the second drying step, when the solvent contained in the solvent-containing resin composition 3 is ethyl acetate, for example, the temperature of the wind A is set to 78 ° C or higher, and the temperature of the wind B is set to 20 ° C to the heat resistance of the base material. The temperature may be less than the temperature.

  Also in the second drying step, in order to suppress deformation of the substrate 2, the temperature of the wind B sprayed on the substrate 2 and the ambient temperature on the substrate 2 side are preferably lower than the heat-resistant temperature of the substrate. . Since the wind A sprayed onto the solvent-containing resin composition 3 is not directly sprayed onto the substrate 2, the temperature of the wind A may be higher than the heat resistance temperature of the substrate 2. It is preferable to adjust the temperature of the wind A so that heat is transferred from the solvent-containing resin composition 3 to the substrate 2 and the substrate 2 does not reach a temperature higher than the heat-resistant temperature.

  When the base material 2 includes polyethylene, the heat resistance temperature of the base material 2 is about 124 ° C. In this case, specifically, for example, the temperature of the wind A is 140 ° C., and the temperature of the wind B is 90 ° C. And it is sufficient.

  It is preferable that the first drying step is performed in the early stage of drying, and the second drying step is performed in the late stage of drying. In this case, the drying time can be further shortened, and the quality of the resin composition after drying can be further enhanced.

  Between the 1st drying process and the 2nd drying process, the temperature of the wind A sprayed on the solvent-containing fat composition 3 and the temperature of the wind B sprayed on the base material 2 are made substantially the same, and drying is performed. May be. For example, when the first drying process is performed in the early stage of drying and the second drying process is performed in the late stage of drying, the temperature of the wind A sprayed on the solvent-containing resin composition 3 and the base material 2 are sprayed in the middle stage of drying. Drying may be performed with the temperature of the wind B being substantially the same. In the middle of drying, the ambient temperature on the solvent-containing resin composition 3 side and the ambient temperature on the substrate 2 side may be substantially equal.

  In the second drying step, the ambient temperature on the solvent-containing resin composition 3 side is increased, so that the solvent can be efficiently evaporated. Moreover, since the solidified skin layer is hard to be formed on the surface of the solvent-containing resin composition 3 in the first drying step, the solvent can be efficiently evaporated in the second drying step. Therefore, the drying time can be shortened.

  Hereinafter, the effects of the present invention will be clarified by giving examples and comparative examples of the present invention. In addition, this invention is not limited to a following example.

(Example 1)
As a base material, a synthetic paper having a thickness of 120 μm having a three-layer structure in which a 10 μm thick polyethylene was provided on both sides of a fine paper having a thickness of 100 μm was prepared. Next, an acrylic polymer solution (resin composition containing a solvent) having an ethyl acetate concentration of 55 wt% was applied to one side of the substrate at 120 g / m ² to obtain a laminate.

  Further, a drying apparatus generally called a floating dryer shown in FIG. 1 was prepared. The nozzle slit of the drying apparatus is 3 mm, the nozzle pitch is 500 mm, and the distance (height direction) between the nozzles on both sides is 10 mm.

  The laminate was placed in the drying apparatus so that the base material was on the lower side and the resin composition was on the upper side, and drying was started. The drying time, that is, the residence time of the laminate in the drying apparatus was 60 seconds. In addition, the wind speed at the time of drying was 10 m / sec.

  The temperatures of wind A and wind B were varied depending on the drying time (initial: 0 to 20 seconds, middle period: 20 to 40 seconds, late period: 40 to 60 seconds). The temperatures of wind A and wind B (wind A and wind B) were 60 ° C. and 115 ° C. (initial), 115 ° C. and 115 ° C. (medium), and 130 ° C. and 100 ° C. (late), respectively.

  The result of having measured the temperature of the base material at the time of drying, the ambient temperature by the side of a base material, and the ambient temperature by the side of a solvent containing resin composition is shown in FIG. The heat-resistant temperature of the synthetic paper as the base material is about 124 ° C., but by setting the temperatures of the wind A and the wind B in the late drying stage to 130 ° C. and 100 ° C., respectively, as shown in FIG. The maximum temperature could be 117 ° C., and the synthetic paper was not deformed.

(Example 2)
The drying time is 54 seconds, and the temperatures of wind A and wind B (wind A and wind B) are 60 ° C. and 115 ° C. (initial: 0 seconds to 18 seconds), 115 ° C. and 115 ° C. (medium period: 18 seconds to 36 seconds) and 130 ° C./100° C. (late stage: 36 seconds to 54 seconds). Drying was performed in the same manner as in Example 1.

(Comparative Example 1)
Implemented except that the temperatures of wind A and wind B (wind A and wind B) were set to 60 ° C / 115 ° C (initial), 115 ° C / 115 ° C (medium), 130 ° C / 130 ° C (late) Drying was carried out in the same manner as in Example 1.

(Comparative Example 2)
Implemented except that the temperatures of wind A and wind B (wind A and wind B) were 115 ° C / 115 ° C (initial), 115 ° C / 115 ° C (middle), 130 ° C / 100 ° C (late) Drying was carried out in the same manner as in Example 1.

(Comparative Example 3)
Implemented except that the temperatures of wind A and wind B (wind A and wind B) were set to 60 ° C. and 115 ° C. (initial), 115 ° C. and 115 ° C. (medium), and 115 ° C. and 115 ° C. (late) Drying was carried out in the same manner as in Example 1.

(Comparative Example 4)
Implemented except that the temperatures of wind A and wind B (wind A and wind B) were 60 ° C / 115 ° C (initial), 115 ° C / 115 ° C (medium), 100 ° C / 130 ° C (late) Drying was carried out in the same manner as in Example 1.

(Comparative Example 5)
Implemented except that the temperatures of wind A and wind B (wind A and wind B) were 115 ° C / 60 ° C (initial), 115 ° C / 115 ° C (medium), 130 ° C / 100 ° C (late) Drying was carried out in the same manner as in Example 1.

(Comparative Example 6)
Implemented except that the temperatures of wind A and wind B (wind A and wind B) were 115 ° C. and 115 ° C. (initial), 115 ° C. and 115 ° C. (medium), and 115 ° C. and 115 ° C. (late) Drying was carried out in the same manner as in Example 1.

(Evaluation)
About the laminated body after drying, the following items were evaluated.

(1) Ethyl acetate concentration The ethyl acetate concentration of the resin composition after drying was evaluated under the following measurement conditions.

  The ethyl acetate concentration was less than 100 ppm as “◎”, 100 ppm or more, less than 200 ppm as “◯”, and 200 ppm or more as “x”, and the results are shown in Table 1 below.

〔Measurement condition〕
Using a thermal desorption device (Perkin Elmer, ATD-400), the amount of organic volatile substances released when the resin composition was heated at 90 ° C. for 30 minutes was measured using a GC-MS device (manufactured by JEOL Ltd., Automass). II-15). Volatile components obtained by heating the resin composition sealed in the sample tube at 90 ° C. for 30 minutes are collected and concentrated in a trap tube built in the thermal desorption apparatus, and then the trap tube is heated at 280 ° C. for 10 minutes. Upon heating, volatile components were introduced into the GC-MS. For the GC-MS measurement, a nonpolar capillary column (HP-1 manufactured by Agilent Technologies, 0.32 mm × 60 m × 0.25 im) was used, and the column temperature was maintained at 40 ° C. for 5 minutes, and then 5 minutes per minute. The temperature was raised to 100 ° C. at a temperature rising rate of ° C. Thereafter, the temperature was raised to 320 ° C. at a rate of 10 ° C. per minute, and then held at 320 ° C. The MS measurement range was 30 to 400 amu, the He flow rate was 1.5 ml / min, the ionization voltage was 70 eV, the ion source was 230 ° C., and the interface was 250 ° C.

  The amount of organic volatile substances is ppm in terms of toluene in which the ethyl acetate peak area is converted to the weight of toluene using an absolute calibration curve created with toluene.

(2) Appearance quality The presence or absence of foaming or bubble entrainment in the resin composition after drying was visually evaluated.

  The case where there was no foaming or bubble entrainment was indicated as “◯”, and the case where there was foaming or bubble entrainment was indicated as “x”.

(3) State of substrate The presence or absence of deformation of the substrate after drying was visually evaluated.

  The case where there was no deformation was indicated by “◯”, and the case where there was deformation was indicated by “X”.

  The results are shown in Table 1 below.

  As shown in Table 1, after the ambient temperature on the base material side is set higher than the ambient temperature on the resin composition side and drying is performed, the ambient temperature on the resin composition side is then set to the ambient temperature on the base material side. By raising the temperature above the temperature and drying, the ethyl acetate concentration could be sufficiently lowered in a short time. Furthermore, the resin composition after drying could be dried without causing surface roughness such as entrainment of bubbles and foaming and without causing deformation of the substrate.

The schematic block diagram which shows the internal structure of the drying apparatus used for the drying method of the solvent containing resin composition which concerns on one Embodiment of this invention. In the drying method of the solvent containing resin composition of Example 1, the figure which shows the change of the temperature of the base material at the time of drying, the ambient temperature by the side of a base material, and the ambient temperature by the side of a solvent containing resin composition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Laminated body 2 ... Base material 2a ... Upper surface 3 ... Solvent containing resin composition 11 ... Drying apparatus 12 ... Nozzle 12a ... Opening hole 13 ... Nozzle 13a ... Opening hole

Claims (3)

A method for drying a solvent-containing resin composition containing a solvent applied to one side of a substrate,
A first drying step in which the ambient temperature on the substrate side is higher than the ambient temperature on the solvent-containing resin composition side;
A solvent-containing resin comprising: a second drying step for setting the ambient temperature on the solvent-containing resin composition side higher than the ambient temperature on the substrate side after the first drying step. A method of drying the composition. A solvent-containing resin composition comprising a solvent applied to one surface of a base material and dried by blowing air on the solvent-containing resin composition,
A first drying step in which the temperature of wind blown onto the substrate is higher than the temperature of wind blown onto the solvent-containing resin composition;
A second drying step for setting the temperature of the wind sprayed on the solvent-containing resin composition higher than the temperature of the wind sprayed on the base material after the first drying step. The drying method of the containing resin composition.   The method for drying a solvent-containing resin composition according to claim 1 or 2, wherein the first drying step is performed at an early stage of drying, and the second drying step is performed at a later stage of drying.

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