JPH0952979A - Cellulose ester film excellent in stability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a cellulose ester film which contains a phosphoric acid ester of a specific chemical structure in a specific proportion and is useful as a substrate for photosensitive materials because the breeding and vaporization are suppressed on its processing with excellent preservation stability. SOLUTION: This cellulose ester film contains (A) 100 pts.wt. of a cellulose ester, preferably cellulose fatty acid ester such as cellulose acetate, cellulose propionate, cellulose butyrate or their mixture and (B) 1-30 pts.wt., more preferably 5-20 pts.wt. of one or two or more kinds of phosphoric esters of the formula (R1 -R4 are each methyl, H; (n) is an integer of 1-5; n1 and n2 are each an integer of 0-2; Q1 and Q4 are each cresyl or xylyl). In the case that cellulose acetate is used as a component A, the acetate has preferably a polymerization degree of 100-400 and the amount of bonded acetic acid is preferably 30-62wt.%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is suitable for use as a support for a memory material such as a photographic material, a release film, a protective film for a polarizing plate, and the like, and prevents bleeding during processing, volatilization, and storage stability. The present invention relates to a cellulose ester film having excellent properties.

[0002]

2. Description of the Related Art Cellulose ester films, particularly fatty acid cellulose esters such as cellulose acetate, cellulose acetate propionate, and cellulose acetate butyrate are widely used commercially, including as a support for photographic light-sensitive materials. These films are generally excellent in dimensional stability and gloss, but have low mechanical properties such as tear strength, folding endurance and impact strength. It has long been known to add a phosphate represented by triphenyl phosphate as a low molecular weight plasticizer in order to improve these properties and impart flame retardancy.

This cellulose ester film is generally produced by a solution casting method in which a dope composed of a cellulose ester, a phosphate and a solvent is cast on a support, a compounding by a thermoplasticization process and an extrusion method in which a film is formed. There is. In these production processes, low molecular weight phosphates such as triphenyl phosphate have a great problem of volatility. This is because, for example, in the solution casting method, the phosphate volatilizes in the solvent evaporation step, and the volatilized phosphate contaminates the film and the phosphate concentration in the film becomes nonuniform.

To solve these problems, high molecular weight plasticizers have been proposed. (Japanese Patent Publication Sho 43-16305
However, these techniques have problems such as a decrease in flame retardance and a large dimensional change of the film. Further, JP-A-6-501039 describes that by blending arylene-bis (diaryl phosphate), excellent properties such as flame retardancy, plasticization and volatility can be obtained.

By the way, in JP-A-6-16869, deterioration of these cellulose ester films during long-term storage is promoted by a strong acid generated by hydrolysis of a contained phosphoric acid ester compound such as triphenyl phosphate. It is described that it will be done. And as a solution to this problem, it is proposed to limit the acid impurities in the phosphoric acid ester compound, but there is a limit to the purification technique for industrially producing such phosphoric acid ester compound. ,Have difficulty.

Therefore, conventionally, a method of incorporating a deterioration inhibitor has been generally used, and an epoxy compound, a saturated polyhydric alcohol, a basic compound, an antioxidant, a peroxide decomposing agent, a radical chain inhibitor, a metal. It is known that an inactivating agent or the like is used alone or in combination (Japanese Patent Laid-Open No. Hei 5-
194789, 6-107854). But,
Some of these deterioration inhibitors have high effects,
Suitable for cellulose ester film, which has the problem of dimensional stability of the film, deterioration of mechanical performance, and volatilization and coloring due to the deterioration inhibitor, and it is not necessary to use them or only a small amount of them is required. The development of phosphate ester compounds has been desired.

[0007]

DISCLOSURE OF THE INVENTION The present invention provides a cellulose ester film which simultaneously satisfies all of the characteristics such as flame retardancy, dimensional stability, mechanical performance, low volatility, uncoloring property, and stability during long-term storage. The challenge is to provide.

[0008]

The present inventors have solved the above problems as a result of intensive studies. (A) 100 parts by weight of cellulose ester,
(B) General formula (I)

[0009]

Embedded image

(Wherein R ₁ , R ₂ , R ₃ and R ₄ represent a methyl group or hydrogen. N is an integer of 1 to 5, n ₁ and
n ₂ represents an integer of 0 to 2. Q ₁ , Q ₂ , Q ₃ , Q ₄
Represents a phenyl group, a cresyl group or a xylyl group, at least one of which is a xylyl group or Q
Invented is a cellulose ester film containing 1 to 30 parts by weight of one or two or more phosphoric acid ester compounds represented by ₁ , Q ₂ , Q ₃ , and Q ₄ are cresyl groups or xylyl groups).

The phosphoric acid ester compound of the component (B) of the present invention has excellent compatibility with cellulose ester, low volatility, thermal stability and hydrolysis stability, and does not require addition of a special deterioration inhibitor. It has an excellent effect of greatly improving the stability of the cellulose ester film.

The present invention will be described in detail below. As the cellulose ester as the component (A) used in the present invention, various cellulose esters that can be formed into a film can be used. Among them, fatty acid cellulose esters such as cellulose acetate, cellulose propionate, cellulose butyrate or mixed esters thereof are particularly preferable. Further, it may have an ester of a higher carbon chain carboxylic acid and other substituents. For example, it may be substituted with a linear or branched alkanoyl group having 1 to 20 carbon atoms, an aroyl group having 7 to 20 carbon atoms, or a heteroaroyl group having 2 to 20 carbon atoms. Substituents having 2 to 8 carbon atoms are generally preferred.

It is necessary that these cellulose esters have a degree of polymerization sufficient to form a film by a solution casting method or an extrusion method. For example, in the case of cellulose acetate, the degree of polymerization is 100 to 400 and the amount of bound acetic acid is. It is preferably 30 to 62%. Degree of polymerization 250
To 400, and an amount of bound acetic acid of 50 to 62% is more preferable. The phosphoric acid ester compound (B) used in the present invention has the general formula (I)

[0014]

Embedded image

In the formula, R ₁ , R ₂ , R ₃ and R ₄ represent a methyl group or hydrogen, n is an integer of 1 to 5, and n ₁ ,
n ₂ represents an integer of 0 to 2, and Q ₁ , Q ₂ , Q ₃ , Q ₄
Is a phenyl group, a cresyl group, or a xylyl group, at least one of which is a xylyl group, or Q ₁ , Q ₂ , Q ₃ , Q ₄ is a cresyl group or a xylyl group. It may be a phosphoric acid ester compound selected from phosphoric acid ester compounds, or may be a mixture thereof.

Further, in the general formula (I), n ₁ , n ₂
Is 0 and R ₃ and R ₄ are preferably methyl groups.
N in the general formula (I) is an integer of 1 to 5, and the flame retarding effect and the plasticizing effect differ depending on the number. When n is larger than 5, the flame retardant effect and the plasticizing effect are reduced. A more preferable range of n is 1 to 3. Also (B)
The component may be a mixture of n-mers.

The phosphoric acid ester compound as the component (B) of the present invention has a binding structure with a specific bifunctional phenol and a terminal structure with a specific monofunctional phenol. As the bifunctional phenol, 2,2-bis (4-hydroxyphenyl) propane [commonly called bisphenol A], 2,2
-Bis (4-hydroxy-3-methylphenyl) propane, bis (4-hydroxyphenyl) methane, bis (4
-Hydroxy-3,5-dimethylphenyl) methane,
Examples include, but are not limited to, bisphenols such as 1,1-bis (4-hydroxyphenyl) ethane. Of these, bisphenol A is particularly preferable.

As the monofunctional phenol, phenol,
Cresol and xylenol can be used alone or as a mixture of two or more kinds, but when only phenol is used, it is not effective in preventing deterioration of the film which is the object of the present invention.
That is, as the monofunctional phenol, in the general formula (I), at least one of Q ₁ , Q ₂ , Q ₃ and Q ₄ is selected to be a xylyl group, or Q ₁ , Q ₂ and
Q ₃ and Q ₄ must be selected to be cresyl or xylyl groups.

The phosphoric acid ester compound as the component (B) can be obtained, for example, by reacting the above-mentioned specific bifunctional phenol and specific monofunctional phenol with phosphorus oxychloride. When this method is used, the structure and the value of n can be adjusted by changing the raw materials in the synthesis reaction, the charging ratio of the raw materials, the order of addition, purifying the products, or mixing the products. . When the phosphate ester compound is used as a mixture, its composition can be analyzed by liquid chromatography or gel permeation chromatography.

The phosphoric acid ester compound as the component (B) has a performance as a flame retardant or a plasticizer for cellulose ester. In addition, volatility is greatly suppressed, and stability and hydrolysis resistance are also excellent. It has good compatibility with cellulose ester and does not cause bleeding from the film at the amount of the present invention required as a plasticizer or flame retardant.

The phosphoric acid ester as the component (B) is a phosphoric acid ester generally used in cellulose ester films within a range that does not impair the effects of the invention, for example, triphenyl phosphate, tricresyl phosphate, trixylenyl phosphate, cresyl. Diphenyl phosphate,
It may contain phosphoric acid esters such as dicresyl phenyl phosphate and hydroxyphenyl diphenyl phosphate, compounds obtained by modifying these with various substituents, various condensation type phosphoric acid ester compounds, and the like. In particular, n in the general formula (1) which may be generated when the phosphoric acid ester compound of the present invention is synthesized from phosphorus oxychloride is 0.
The compound may be mixed in a range not exceeding 30% by weight of the whole phosphoric acid ester compound.

The phosphoric acid ester compound as the component (B) is a compound in which two or more phosphoric acid esters are bound by a specific bifunctional phenol such as bisphenol, and the volatility thereof is greatly suppressed. Moreover, special table flat 6-5
Conventional arylene-bis (diallyl phosphate) compounds specifically shown in JP-A-01039, for example, those bound with resorcinol or hydroquinone, or those bound with bisphenol A without any monofunctional phenol at the end being substituted. Shows a very high hydrolysis stability that could not be achieved with. Therefore, when using a conventional phosphate ester, it is possible to suppress the deterioration of the cellulose ester that occurred in the exposure test under high temperature and high humidity conditions,
An excellent cellulose ester film that maintains initial properties can be obtained.

In the cellulose ester film of the present invention, the phosphate ester compound as the component (B) is 1 to 30 parts by weight, more preferably 5 to 20 parts by weight, relative to 100 parts by weight of the cellulose ester as the component (A). included. When the amount of the phosphoric acid ester compound as the component (B) is less than 1 part by weight, the effect of flame retardancy and plasticity is lost, and when it is more than 30 parts by weight, the mechanical performance of the film deteriorates.

The cellulose ester film of the present invention may contain other additives, if necessary, within a range not impairing the effects of the present invention. Examples of other additives include other plasticizers such as phthalic acid esters, peeling aids, heat stabilizers, antioxidants, ultraviolet absorbers, acid scavengers and the like.

The method for producing the cellulose ester film is not particularly limited, and any method commonly used in the art can be used. Using a good solvent of cellulose ester such as methylene chloride as a solvent, or a mixed solvent with a poor solvent such as alcohols, a solution containing cellulose ester, a phosphate ester compound, and other additives is prepared and poured onto a support. The method of rolling, stripping and drying is well known (Japanese Patent Laid-Open No. 176834/1985).
(See gazettes of the same 60-203430).

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to examples. In the examples, as the cellulose ester, cellulose acetate having an average degree of polymerization of 260 and a bound acetic acid content of 60% was used.

The phosphoric acid ester compounds used in the examples are shown in Table 1, and the phosphoric acid ester compounds used in the comparative examples are shown in Table 2. The composition of the phosphoric acid ester compounds in the table was determined by Shimadzu's Shim-
Pack GPC801C and Shim-Pack GP
Using a column in which C802C was connected in series, chloroform was used as the developing solution, the developing solution flow rate was 1.0 ml / min, and the temperature was 3
It analyzed using the UV detector of wavelength 254nm on condition of 0 degreeC.

The film was prepared by dissolving cellulose acetate in a solvent of methylene chloride / methanol 9/1 by weight, mixing a predetermined amount of the phosphoric acid ester compound with the solution, and then casting the solution on a glass plate. , And dried by heating. The film thickness is 0.2
It was prepared so as to be mm. Regarding the appearance, the bleeding state and color of the phosphoric acid ester compound were visually determined.

The volatility was evaluated by TGA analysis of the film at a temperature at which a weight loss of 3% by weight with respect to the original weight was observed when the temperature was raised at 40 ° C./min in a nitrogen atmosphere. The flame retardancy was evaluated by the TGA analysis of the film at a temperature of 40 ° C./min in a nitrogen atmosphere and evaluated by% of the residual weight with respect to the original weight when reaching 850 ° C. Generally, the larger the residual weight, the better the flame retardancy.

Further, regarding the flame retardancy, the film was cut into a size of 100 mm × 10 mm, and this test piece was used in accordance with the test method of UL94. That is, the film was fixed vertically, the burner flame was applied to the center of the lower end for 10 seconds, and the burning time was observed. As soon as the flame of the test piece disappeared, the burner flame was again applied for 10 seconds and the burning time was removed. Was observed. The average of the first and second burning times was taken as the average burning time.

The deterioration prevention effect was evaluated by exposing the film to a relative humidity of 100% and a temperature of 90 ° C. for 120 hours. The film before and after the exposure test is washed with methanol to remove components other than cellulose acetate,
After drying, the reduced viscosity was measured. Reduced viscosity is 60 at 25 ℃
Measured at a concentration of 0.5 grams per 100 milliliters of solvent in a phenol / tetrachloroethane solvent in a weight ratio of / 40. The deterioration preventing effect was evaluated by the reduced viscosity retention rate, which is the ratio of the reduced viscosity after the exposure test to the reduced viscosity before the exposure test expressed as a percentage.

[0032]

【Example】

Example 1 A film was prepared by using 10 parts by weight of the phosphoric acid ester compound A shown in Table 1 in 90 parts by weight of cellulose acetate. The evaluation results are shown in Table 3.

Examples 2 and 3 Films were similarly prepared by changing the amounts of cellulose acetate and phosphate ester compound A used. The evaluation results are shown in Table 3.

Examples 4, 5 Films were prepared in the same manner as in Example 1 using 10 parts by weight of the phosphoric acid ester compounds B and C shown in Table 1, and the evaluation results are shown in Table 3.

Comparative Examples 1, 2, 3, 4 Phosphate ester compounds D, E, F and G shown in Table 2
10 parts by weight of was used to prepare a film in the same manner as in Example 1, and the evaluation results are shown in Table 4.

Comparative Example 5 A film was prepared in the same manner as in Example 1 using 20 parts by weight of the phosphoric acid ester compound G shown in Table 2, and the evaluation results are shown in Table 4.

[0037]

[Table 1]

[0038]

[Table 2]

[0039]

[Table 3]

[0040]

[Table 4]

[0041]

EFFECTS OF THE INVENTION The cellulose ester film of the present invention has the effect of simultaneously satisfying all the characteristics such as flame retardancy, dimensional stability, mechanical performance, low volatility, uncoloring property, and stability during long-term storage. Have.

Claims (2)

[Claims] 1. To 100 parts by weight of (A) cellulose ester, (B) general formula (I): (In the formula, R ₁ , R ₂ , R ₃ , and R ₄ represent a methyl group or hydrogen. N is an integer of 1 to 5, n ₁ and n ₂ are integers of 0 to 2. Q ₁ , Q ₂ , Q ₃ and Q ₄ represent any of a phenyl group, a cresyl group and a xylyl group, at least one of which is a xylyl group, or Q ₁ , Q
₂ , Q ₃ and Q ₄ are cresyl groups or xylyl groups) or a phosphoric ester compound represented by
A cellulose ester film comprising 1 to 30 parts by weight of at least one kind. 2. The cellulose ester film according to claim ₁ , wherein in the phosphoric acid ester compound as the component (B), n ₁ and n ₂ are 0 and R ₃ and R ₄ are methyl groups.