JPH06313100A - Polycarbonate solution composition - Google Patents

Abstract

PURPOSE:To obtain a polycarbonate solution composition capable of being used for forming films or for coating films. CONSTITUTION:This polycarbonate solution composition contains 10-35 pts.wt. of a polycarbonate and 100 pts.wt. of a solvent mixture comprising 20-60wt.% of 1,3-dioxorane and the remaining amount of a solvent having a specific solubility parameter.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a polycarbonate solution composition.

[0002]

2. Description of the Related Art Polycarbonate is used as a thermoplastic resin in a large amount of various molded articles such as automobile parts, helmets, industrial materials, and electric equipment parts from the viewpoint of its mechanical strength and thermal stability. Has been done. Along with that, it is also used in film or sheet form.
Apart from such molded articles, they are also used for so-called coating applications. Among them, for film and coating applications, they are mainly produced by coating or coating a solution of polycarbonate dissolved in an organic solvent. As the organic solvent used in these, dichloromethane has been mainly used conventionally. However, in recent years, from the viewpoint of the global environment, the use of chlorine-based solvents containing dichloromethane has tended to be restricted. Moreover, since dichloromethane has a low boiling point (41 ° C.), it is likely to volatilize during film forming and coating operations, which poses a problem from the working environment. Therefore, there is an increasing demand for a technique of forming a film or coating from a new solvent. However, solvents other than dichloromethane have various problems such as solubility, solution stability, and smoothness of coating film surface, and solvents satisfying these problems have not yet been put into practical use.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a new stock solution for film-forming or coating a polycarbonate solution composition. Generally, the properties required for these solution compositions are (1) high-concentration dissolution, (2) stable solution composition, (3) easy evaporation and removal, (4) uniform and smooth surface It is required to provide a film or coating.
Therefore, it is an object of the present invention to solve these problems.

[0004]

The present inventors have previously
We have found that 3-dioxolane is a good solvent for polycarbonate and have already proposed it. As a result of further examination after that, by mixing a solvent having a certain solubility parameter range, not only a mixed solvent capable of dissolving polycarbonate at a high concentration but also a uniform and smooth coating surface can be obtained. Found and arrived at the present invention. These solvents are good solvents for polycarbonate, and when mixed, the low-boiling point components mainly evaporate first and the high-boiling point solvent evaporates later at the initial stage of film formation or coating. Therefore, even if the low-boiling solvent evaporates from the surface, the high-boiling solvent diffuses from the inside toward the surface, and the difference in dryness between the inside and the surface, in other words, the concentration gradient of the solvent is smaller than that in the case of a single solvent. When dried with a single solvent, the surface layer is first in an over-dried state, and the inside is often in a significantly under-dried state, which causes non-uniformity. However, if a solvent having a high boiling point in the mixed solvent is a poor solvent for the polycarbonate, the polycarbonate may be precipitated or crystallized during the drying process, so that a transparent film or coating film cannot be obtained. Therefore, we focused on the solubility parameter, which is a measure of polymer affinity.

That is, the present invention provides 1,2-dioxolane with 2
With respect to 100 parts by weight of the mixed solvent containing 0 to 60% by weight,
A polycarbonate solution composition comprising 10 to 35 parts by weight of a polycarbonate resin.

The mixed solvent contains 20 to 60% by weight of 1,3-dioxolane (solvent I), and the remaining components have a solubility parameter (δv) defined by the following formula of 17 to 22.
(J / cm ³ ) ^1/2 range,

[0007]

## EQU2 ## δv = (δd ² + δp ² ) ^1/2 [δd is a solubility parameter based on the dispersion term, and δp
Is the solubility parameter based on the polarization term. ] And the solubility parameter (δh) based on the hydrogen bond term is 4 to 10
(J / cm ³⁾ is preferably at least one selected from ^1/2 of the other solvents in the range (solvent II).

The solvent II is preferably at least one selected from dioxane, tetrahydrofuran, 1,2-dichloroethane, cyclohexanone and chlorobenzene.

The viscosity average molecular weight of the polycarbonate resin is preferably 8,000 or more and 70,000 or less.

The solution composition has a temperature (Tb-1) of 40 ° C. or higher.
5) ° C [however, Tb represents the lower boiling point of dioxolane and the solvent (II). ] It is preferable to dissolve and store below.

The present invention will be described in detail below.

The polycarbonate used in the present invention is a polycarbonate containing mainly bisphenol-A as a phenol component. However, it may be a copolymer containing 20 mol% or less of another bisphenol component or dicarboxylic acid component in order to change its physical properties depending on the application. The copolymerization component is not particularly limited, but it is 2,2-propylenebis (3-methyl-4-hydroxybenzene), 2,2-propylenebis (3,5-dimethyl-4-hydroxybenzene), 2, 2-propylenebis (3,5-dibromo-4-hydroxybenzene), 1,1-cyclohexylenebis (4-hydroxybenzene), 1,1-cyclohexylenebis (3-methyl-4-hydroxybenzene), 1 , 1- (3, 3, 5
-Trimethylcyclohexylene) bis (4-hydroxybenzene), 2,2-butylenebis (4-hydroxybenzene), 2,2- (3-methylpentylene) bis (4
-Hydroxybenzene) and the like. Examples of the dicarboxylic acid component include isophthalic acid and terephthalic acid.

The viscosity average molecular weight of the polycarbonate used here is preferably 8,000 or more and 70,000 or less, more preferably 10,000 or more and 50,000 or less. When the amount is less than this range, the physical properties of the film and the coating film are deteriorated, which is not preferable. The viscosity average molecular weight is 0.5 g / 1 of polycarbonate in dichloromethane.
It is determined from the intrinsic viscosity obtained from a solution in which 00 ml is dissolved.
This value is Mark-Hoink-Sakurada (Mark-Ho
It can be calculated from the formula of “wink-Sakurada”. The way to ask is the Polymer Handbook, 3rd revised edition, Willi Co. (1989) (Polymer Handbook).
3rd Ed. Willey, 1989), pages 7-23.

In the present invention, the mixed solvent containing 1,3-dioxolane is a mixed solvent containing 20 to 60% by weight of 1,3-dioxolane. If the concentration of 1,3-dioxolane is less than 20% by weight or more than 60% by weight, the characteristics of the mixed solvent are lost, which is not preferable. That is, as described above, the low-boiling point component and the high-boiling point component are sequentially evaporated, so that the effect of making the solvent distribution in the film or the coating film uniform is not exhibited.

The concentration of the polycarbonate is at least 10 to 35 parts by weight, preferably 15 to 30 parts by weight, based on 100 parts by weight of the mixed solvent. When the ratio of the polycarbonate exceeds this range, crystallization is observed even in this mixed solvent, and the fluidity is remarkably lowered, which is not preferable. On the other hand, if the ratio is less than this, there is no problem with the stability of the polycarbonate solution composition, but the working concentration of the polycarbonate decreases, which is not preferable in practice.

The solvent (solvent II) other than 1,3-dioxolane used in the present invention has a solubility parameter (δv) defined by the following formula in the range of 17 to 22 (J / cm ³ ) ^1/2 . ,

[0017]

## EQU3 ## δv = (δd ² + δp ² ) ^1/2 [δd is a solubility parameter based on the dispersion term, and δp
Is the solubility parameter based on the polarization term. ] And the solubility parameter (δh) based on the hydrogen bond term is 4 to 10
(J / cm ³⁾ in ^1/2 range. The solubility parameter is generally known as a measure of the solubility of solvent molecules. However, originally, the solubility parameter is a parameter focused only on the dispersive property (δd) of solvent molecules. However, in order to make the characterizations of many solvents more accurate, a concept was further extended to the polarizable properties (δp) and hydrogen bonding properties (δh) of solvent molecules. The present inventors have studied the solubility parameters of the solvent (I), the solvent (II) and the polycarbonate in detail, and as a result, arranged by using the parameters (δv) and δh derived by the above equation, Succeeded in obtaining the selection guideline. Here, δv of polycarbonate is 19 (J
/ Cm ³ ) ^1/2 and δh is 7 (J / cm ³ ) ^1/2 . In addition, δv of dioxolane is 17.1 (J / cm ³ ).
^1/2 and δh is 9.3 (J / cm ³ ) ^1/2 . When the δv of the solvent II used in the present invention is less than 17, the contribution of dispersion and the contribution of polarization are too small and the affinity with polycarbonate is lowered, and conversely, when it exceeds 22, it is too large and the affinity is lowered. To do. On the other hand, when δh is less than 4, the association due to hydrogen bond formation with the polycarbonate is inhibited, which is not preferable, and when it exceeds δh, the hydrogen bonding property of the polycarbonate and the property of the solvent do not match, which is not preferred. Regarding the solubility parameter,
D. W. Krevelen "Properties o
f Polymers ", 3rd Ed. Elsevi
er (1992), pp189-225 and pp77.
4 to 789.

As the solvent II, dioxane [δv =
18.4 (J / cm ³ ) ^1/2 , δh = 7.4 (J / cm
³ ) ^1/2 ], tetrahydrofuran [δv = 18.8 (J
/ Cm ³ ) ^1/2 , δh = 8.0 (J / cm ³ ) ^1/2 ],
Dichloromethane [δv = 19.0 (J / cm ³ ) ^1/2 ,
δh = 6.1 (J / cm ³ ) ^1/2 ], chloroform [δ
v = 18.2 (J / cm ³ ) ^1/2 , δh = 5.7 (J /
cm ³ ) ^1/2 ], 1,2-dichloroethane [δv = 1
8.9 (J / cm ³ ) ^1/2 , δh = 4.1 (J / c
m ³ ) ^1/2 ], 1,1,2,2-tetrachloroethane [δv = 19.2 (J / cm ³ ) ^1/2 , δh = 4.0
(J / cm ³ ) ^1/2 ], cyclohexanone [δv = 1
9.6 (J / cm ³ ) ^1/2 , δh = 5.1 (J / c
m ³ ) ^1/2 ], chlorobenzene [δv = 20.3 (J /
cm ³ ) ^1/2 , δh = 4.1 (J / cm ³ ) ^1/2 ]. Of these, dioxane, tetrahydrofuran, 1,2-dichloroethane, cyclohexanone, and chlorobenzene are preferably used in consideration of the problem of toxicity.
These solvents may be one kind or two kinds.

To prepare these solutions, a predetermined amount of polycarbonate may be put in a mixed solvent and dissolved by stirring at a predetermined temperature. The dissolution temperature is a point where a high concentration is obtained and the stability of the solution is enhanced. In consideration of the point and the film forming (drying) temperature, it is preferable to heat and dissolve. The preferred temperature range is 4
0 ° C. or higher, (Tb-15) ° C. [wherein, Tb represents the boiling point of the low boiling point component of dioxolane and the solvent (II). ] The following is selected. If it is lower than 40 ° C, the solubility is lowered, the crystallization is likely to occur, and the viscosity is remarkably increased, which is not preferable. On the contrary, if it exceeds it, it must be dissolved under pressure, which is not preferable in practice.

[0020]

EFFECTS OF THE INVENTION According to the present invention, there is provided a good polycarbonate solution composition which does not cause turbidity due to crystallization or the like. Such compositions are well suited for use in homogeneous polycarbonate films or coatings.

[0021]

EXAMPLES The present invention will be described in detail below with reference to examples. However, the present invention is not limited to this.

[0022]

Example 1 Polycarbonate resin containing bisphenol-A as a bisphenol component (viscosity average molecular weight 44.0)
00) 25 parts by weight is added to a mixed solvent consisting of 50 parts by weight of 1,3-dioxolane and 50 parts by weight of tetrahydrofuran, and heated and stirred at 45 ° C. for 8 hours to dissolve,
A clear viscous solution composition was obtained. The obtained solution did not crystallize or gel even if it was allowed to stand at that temperature for 48 hours. This solution was cast on a stainless steel substrate heated to 40 ° C. using a doctor knife having a clearance of 0.8 mm, and then dried at 80 ° C. for 1 hour in a hot air drier to obtain a transparent film. The tensile strength of this film is 6.3 kg / mm ² , and the breaking elongation is 10.
It was 5% and the elastic modulus was 120 kg / mm ² .

[0023]

Comparative Example 1 Tetrahydrofuran of Example 1 was converted into methyl isobutyl ketone [δv = 16.5 (J / cm ³ ) ^1/2 ,
.delta.h = 4.1 by replacing ^{(J / cm 3) 1/2]} , others have been dissolved polycarbonate by the method of Example 1, a homogeneous solution was not obtained.

[0024]

Comparative Example 2 Tetrahydrofuran of Example 1 was mixed with propylene carbonate [δv = 27.0 (J / cm ³ ) ^1/2 ,
.delta.h = 4.1 by replacing ^{(J / cm 3) 1/2]} , others have been dissolved polycarbonate by the method of Example 1, a homogeneous solution was not obtained.

[0025]

Comparative Example 3 The tetrahydrofuran of Example 1 was 1,1,
1-trichloroethane [δv = 17.3 (J / cm ³ )
^1/2 , δh = 2.0 (J / cm ³ ) ^1/2 ], but the polycarbonate was dissolved in the same manner as in Example 1 except that a uniform solution was not obtained.

[0026]

Example 2 25 parts by weight of the polycarbonate used in Example 1 was dissolved in a mixed solvent of 25 parts by weight of 1,3-dioxolane and 75 parts by weight of 1,2-dichloroethane by heating at 60 ° C. to obtain a uniform solution. It was This solution was kept at the same temperature for 48 hours, but no crystallization or gelation was observed. A strong transparent film was obtained from this solution by film casting on a stainless steel substrate heated to 50 ° C.

[0027]

Comparative Example 4 Polycarbonate was dissolved in the same manner as in Example 2 except that 100 parts by weight of 1,2-dichloroethane was used as the mixed solvent in Example 2, but a uniform solution was not obtained.

[0028]

Examples 3 to 7 A dissolution test was conducted on a polycarbonate resin containing bisphenol-A as a bisphenol component while changing the molecular weight, the type of solvent, the concentration, and the dissolution / storage temperature. The results are shown in Table 1. As is clear from the table, viscous transparent solution compositions were obtained, and these solutions were kept at the same temperature and cast from them to obtain a transparent film (100 μm) (Table 2). The viscous solution composition thus obtained was allowed to stand at the same temperature for 48 hours.
In neither case was crystallization (gelation) observed.

[0029]

[Table 1]

[0030]

[Table 2]

[0031]

[Embodiment 8] Bisphenol component is bisphenol-A
20 parts by weight of a polycarbonate (viscosity average molecular weight 42,000) consisting of 96 mol% of the component and 4 mol% of 1,1-cyclohexylene bis (4-hydroxybenzene) (bisphenol-Z) was added to 50 parts of 1,3-dioxolane.
The mixture was added to a mixed solvent composed of 50 parts by weight of tetrahydrofuran and 50 parts by weight of tetrahydrofuran, and heated and stirred at 80 ° C. for 8 hours to obtain a transparent viscous solution. This solution was allowed to stand at the same temperature for 48 hours, but no crystallization or gelation occurred, and no change in viscosity was observed. A film was cast from these solutions in the same manner as in Example 1 to obtain a transparent film.

[0032]

[Example 9] Bisphenol component is bisphenol-A
Ingredient 93 mol% and 1,1- (3,3,5-trimethylcyclohexylene) bis (4-hydroxybenzene)
20 parts by weight of polycarbonate (viscosity average molecular weight 38,000) consisting of 7 mol% of the component was added to 1,3-dioxolane 5
The mixture was added to a mixed solvent consisting of 0 parts by weight and 50 parts by weight of tetrahydrofuran, and heated and stirred at 80 ° C. for 8 hours to obtain a transparent viscous solution. This solution was allowed to stand at the same temperature for 48 hours, but no crystallization or gelation occurred, and no change in viscosity was observed. A film was cast from these solutions in the same manner as in Example 1 to obtain a transparent film.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical indication location C09D 169/00 PLP 9363-4J (72) Inventor Yumin Yonemura 4-3 Asahigaoka, Hino-shi, Tokyo No. 2 Teijin Limited Tokyo Research Center

Claims (4)

[Claims] 1. A polycarbonate solution composition comprising 10 to 35 parts by weight of a polycarbonate resin with respect to 100 parts by weight of a mixed solvent containing 20 to 60% by weight of 1,3-dioxolane. 2. The mixed solvent contains 20 to 60% by weight of 1,3-dioxolane (solvent I), and the remaining components are:
The solubility parameter (δv) defined by the following formula is 17 to
22 (J / cm ³ ) ^1/2 , and δv = (δd ² + δp ² ) ^1/2 [δd is a solubility parameter based on the dispersion term, and δp
Is the solubility parameter based on the polarization term. ] And the solubility parameter (δh) based on the hydrogen bond term is 4 to 10
^{(J / cm 3) 1/} 2 other solvents ranges polycarbonate solution composition of claim 1, wherein the at least one selected from (solvent II). 3. The polycarbonate solution composition according to claim 1, wherein the solvent II is at least one selected from dioxane, tetrahydrofuran, 1,2-dichloroethane, cyclohexanone and chlorobenzene. 4. The viscosity average molecular weight of the polycarbonate resin is 8,000 or more and 70,000 or less.
The polycarbonate solution composition described.