JP2002166458A - Method for manufacturing norbornene resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a norbornene resin film having no appearance defectiveness such as the deteriorated resin caused by thermal deterioration, a die line, air bubbles or the like, not lowered in strength and not generating these problems even if a polymer film is used. SOLUTION: In the method for manufacturing the norbornene resin film by melt extrusion molding, a ratio Mw2/Mw1 of the weight average mol.wt. (Mw1) before extrusion molding and the weight average mol.wt. (Mw2) after extrusion molding is 0.87-1.03.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a norbornene resin film. In the present specification, the film is not limited to a film in a strict sense based on the thickness, but includes a relatively thick film generally called a sheet.

[0002]

2. Description of the Related Art Norbornene resins have the following advantages over other resins. (1) High heat resistance. (2) High transparency. (3) No optical rotation. (4) Low intrinsic birefringence. (5) The photoelastic coefficient is small. Therefore, it is suitable as an optical film used for a display or the like.

However, due to its poor thermal stability,
There is a problem that melt molding is difficult.

Accordingly, norbornene resins having a relatively high molecular weight (weight average molecular weight Mw: 100,000 to 2,000,000) and a wide molecular weight distribution (Mw / Mn ≧ 2.2, Mn: number average molecular weight) and molding using the same A product has been proposed (Japanese Patent No. 2977274). This makes it possible to produce a flat and beautiful molded product that solidifies gradually during melt molding and has little residual stress.

However, in general, norbornene resins are
Even if an antioxidant is added, thermal decomposition starts at about 260 ° C. in the air. On the other hand, the melt extrusion molding temperature of the norbornene-based resin is a high temperature near 300 ° C.

Accordingly, in melt extrusion molding of norbornene-based resin, a gel-like substance or the like is generated by thermal decomposition at a high molding temperature, and thus a molded article is liable to cause a point defect.

On the other hand, films used for optical applications are required to be free from point defects. Therefore, in order to remove a gel-like substance and a foreign substance in a resin generated by thermal decomposition with high accuracy, a very fine filtration device called a polymer filter is used.

However, since the above-mentioned resin has a high molecular weight, the resin has a high melt viscosity. Therefore, in order to pass through the above-mentioned fine polymer filter, a long residence time is required in order to secure a large filtration area at a high temperature. As a result, even after passing through the filter, new gel-like substances, foreign substances, and low-molecular-weight volatile components are generated by thermal decomposition, and poor appearance such as eye grease, die lines, and bubbles are generated on the film. Was very brittle and could only obtain a material whose strength was so remarkably reduced that it could be easily broken even by bending.

[0009]

The problem to be solved by the present invention is disclosed in
No. 251342 discloses a weight average molecular weight of 80,000 to 140,
000, a method for melt-extruding a norbornene resin film having a molecular weight distribution (Mw / Mn) of 4 to 6 at an extruder residence time of 15 to 30 minutes, an extruder cylinder and a die temperature of 280 to 320 ° C. I have.

However, in this manufacturing method,
Since the molecular weight distribution is very wide, volatilization of low molecular weight components and
The problem of decomposition of high molecular weight components remains.

The present invention solves the above-mentioned problems, and a first object of the present invention is to provide a method for producing a norbornene-based resin film which is free from poor appearance such as grease, die lines, air bubbles, and the like due to thermal deterioration and strength. In addition, a second object is to provide a method for producing a norbornene-based resin film in which the above-mentioned problem does not occur even when a polymer filter is used.

[0012]

A method for producing a norbornene-based resin film according to claim 1 (hereinafter referred to as "the present invention 1") is a method for producing a norbornene-based resin film by melt extrusion. the weight average molecular weight of the resin (Mw ₁₎ and a weight average molecular weight of the film after the extrusion (Mw ₂₎ the ratio Mw ₂ / Mw ₁ and is from 0.87 to 1 in.
03.

The norbornene-based resin used in the present invention 1 is a polymer containing a norbornene-based monomer as a main component, for example, a hydrogenated product of a ring-opened polymer of a norbornene-based monomer and an addition of a norbornene-based monomer. Polymers, addition polymers of norbornene-based monomers and olefin-based monomers, and modified products thereof. These may be used alone or in combination of two or more.

If the weight-average molecular weight (Mw) of the norbornene resin is too low, the melt viscosity is reduced and the moldability is improved, but the mechanical strength of the obtained film is reduced.
If the post-process such as paper passing, trimming, cutting, etc. is hindered, the melt viscosity will be high if it is too high, extrusion molding will be difficult at low temperature, and if extrusion molding is performed at high temperature, the resin will deteriorate, 50,000 to 150,000 is preferred because the resulting film has poor appearance and reduced strength.

The weight-average molecular weight (Mw) can be measured by a LALLS method using a laser, an HPLC method such as gel permeation chromatography analysis (GPC method), or the like.

If the molecular weight distribution of the norbornene-based resin is too wide, problems such as volatilization of low molecular weight components and decomposition of high molecular weight components occur, so that the weight average molecular weight (Mw) and the number average molecular weight (Mn) are not equal. The ratio (Mw / Mn) is preferably 4 or less.

The above norbornene-based resin may be used, if necessary, in order to improve the heat resistance, weather resistance, smoothness, etc. of the film as long as the effects of the present invention are not impaired. Agents: Thermal deterioration inhibitors such as phenols; Antistatic agents such as amines; Lubricants such as esters of fatty alcohols and partial esters of polyhydric alcohols; Ultraviolet absorbers such as benzophenones, benzotriazoles, and acrylonitrile; Nonionic surfactant;
An additive such as a special acrylic resin-based or silicone-based leveling agent may be added.

In the case of using the above-mentioned additives or a plurality of resins, when measuring the weight average molecular weight (Mw ₁ ) of the resin before extrusion molding, when the raw materials are collectively supplied to the extruder, The resin composition supplied to the extruder may be subjected to measurement as it is.However, when the resin composition is divided and supplied to the extruder, small extrusion is performed so as not to apply a heat load to the resin composition as much as possible. What is mixed in a short time with a machine, a lab plastmill, a roll, or the like may be used for the measurement.

In the present invention 1, the weight average molecular weight (Mw ₁ ) of the resin before extrusion molding and the weight average molecular weight of the film after extrusion molding of the norbornene resin or the composition thereof are measured as described above. Melt extrusion molding is performed so that the ratio Mw ₂ / Mw ₁ to Mw ₂ ) is 0.87 to 1.03.

When the value of Mw ₂ / Mw ₁ is less than 0.87, the norbornene-based resin is significantly deteriorated, resulting in poor appearance and reduced strength such as grease, die lines, and bubbles due to thermal deterioration. In addition, if it exceeds 1.03, it is considered that the tendency of gel generation is shown even when the measurement error is considered.
0.87 to 1.03, preferably 0.9 to 1
It is.

The method for producing a norbornene-based resin film according to claim 2 (hereinafter referred to as "the present invention 2") is a method for producing a norbornene-based resin film by melt extrusion molding, wherein the resin has a weight average molecular weight before extrusion molding. (M
w ₁ ) and the ratio Mw ₃ / Mw ₁ of the weight average molecular weight (Mw ₃ ) of the resin predicted from the temperature history in melt extrusion molding are 0.8.
7 to 1.03.

The method for measuring the norbornene resin used in the present invention 2 and the weight average molecular weight (Mw ₁ ) of the resin before extrusion molding are the same as those of the present invention 1.

In producing a norbornene resin film by melt extrusion, the norbornene resin undergoes various temperature histories in an extruder. This temperature history differs for each zone of the extruder, the polymer filter, the mold, and the like. Then, as shown in the present invention 1, it is good if the weight average molecular weight (Mw ₂ ) of the film after extrusion molding can be measured, but it is not possible to perform all measurements in various cases with different manufacturing conditions and equipment configurations. Very inefficient. Therefore, based on the assumed equipment and manufacturing conditions used for melt extrusion, the temperature history T = f ₁ (t) received for each part (where T: temperature, t: time) Mw ₃ is calculated from the weight average molecular weight (hereinafter referred to as “predicted function of molecular weight decrease after molding”) Mw ₃ = Mw ₁ −Δf ₂ (T) dt, and Mw ₃ / Mw ₁ is 0.87 to 1.03. The melt extrusion molding is performed so that

The function Mw _{3 for} predicting a decrease in molecular weight after molding is as follows:
For example, a raw resin is left in an oven at several temperature levels and time levels, and the weight average molecular weight of each is measured.
From the result, it is obtained by approximating the maximum likelihood function, and a decrease in molecular weight with respect to the assumed temperature history is predicted.

According to a third aspect of the present invention, there is provided a method for producing a norbornene-based resin film by melt extrusion molding using a filtration device comprising a polymer filter.
The weight average molecular weight (Mw ₁ ) of the resin before extrusion molding,
Assuming that the set temperature of the polymer filter is T and the residence time of the resin in the polymer filter is t, the ratio to the weight average molecular weight (Mw ₄ ) at the temperature T and time t predicted from the change in the molecular weight of the resin. Mw ₄ / Mw ₁ is 0.87 ~
1.03.

The method for measuring the norbornene resin used in the present invention 3 and the weight average molecular weight (Mw ₁ ) of the resin before extrusion molding are the same as those of the present invention 1 or 2.

When a polymer filter is used, the residence time in the polymer filter is usually much longer than in other parts, so that most of the decrease in the molecular weight of the norbornene resin is caused by passing through the polymer filter. appear. Therefore, when a decrease in molecular weight upon passing through a polymer filter is predicted and the value is defined as Mw ₄ , Mw ₄
Melt extrusion molding is performed so that / Mw ₁ is 0.87 to 1.03.

The polymer filter used in the present invention 3 is not particularly limited, and examples thereof include a disk type, a candle type, and a leaf disk.
This is preferable because the residence time is relatively short. The polymer filter is preferably designed so that its residence time distribution is as small as possible. The filter material constituting the filter is appropriately selected in consideration of the quality of the norbornene-based resin film to be produced, the mechanical strength of the polymer filter itself, molding conditions, and the like.

(Function) The present invention 1 relates to a method for producing a norbornene resin film by melt extrusion molding, wherein the weight average molecular weight (Mw ₁ ) of the resin before extrusion molding and the weight average molecular weight of the film after extrusion molding (Mw ₁ ) Since the ratio Mw ₂ / Mw ₁ to Mw ₂ ) is 0.87 to 1.03, generation of low molecular weight components, gel components, bubbles and the like can be suppressed.

The present invention 2 relates to a method for producing a norbornene-based resin film by melt-extrusion molding, wherein the weight-average molecular weight (Mw ₁ ) of the resin before extrusion, the molecular weight reduction predicting function (Mw ₃ ) after molding, and the like. The ratio Mw ₃ / Mw ₁ is 0.87 ~
Since it is 1.03, even if the weight average molecular weight of the actually obtained film is not measured, the low molecular weight component, the gel component,
Generation of bubbles and the like can be suppressed.

The present invention 3 relates to a method for producing a norbornene-based resin film by melt-extrusion using a filtration device comprising a polymer filter, wherein the weight-average molecular weight (Mw ₁ ) of the resin before extrusion is determined. When the set temperature is T and the residence time of the resin in the polymer filter is t, the ratio Mw ₄ / to the weight average molecular weight (Mw ₄ ) at the temperature T and time t, which is predicted from the change in the molecular weight of the resin. Since Mw ₁ is 0.87 to 1.03, the polymer can be obtained without measuring the weight-average molecular weight of the actually obtained film or measuring the temperature history applied to each part of the extruder. Only by determining the residence time of the resin in the filter, the generation of low molecular weight components, gel components, bubbles and the like can be suppressed.

[0032]

Next, the present invention will be described in detail with reference to examples.

(Examples 1 and 2, Comparative Examples 1 and 2) Norbornene resin having a weight average molecular weight Mw ₁ and a number average molecular weight shown in Table 1 (trade name "ARTON" manufactured by JSR Corporation)
After drying at 110 ° C. for 3 hours, a single screw extruder (φ50
mm, L / D = 28), extruded at 275-320 ° C., and sent to a gear pump at a flow rate of 16 kg / hr.
Furthermore, a polymer filter (sintered metal fiber type, filtration accuracy 3 μm, flow rate 20
(residence time of 29 minutes at kg / hr) was filtered and discharged from a T-die (width 500 mm, coat hanger type). Next, the discharged resin was formed into a film by a cooling roll set at 115 to 145 ° C.
A norbornene-based resin film having a thickness of 50 mm and a thickness of 50 mm was obtained.

The weight-average molecular weight Mw ₁ and the number-average molecular weight of the resin were determined by a GPC method using a high performance liquid chromatograph (manufactured by Hitachi, Ltd., pump: model “L-6000”, detector: model “L-3300RI”). , Column: Model “HSG
60 + 30 + 20 ”), using tetrahydrofuran (1.0 mL / min) as a carrier, and expressed in terms of polystyrene. Measurement temperature is room temperature, injection amount is 10
0 μL. As a test sample, 20 mg of the resin was dissolved in 5 mL of tetrahydrofuran, and after standing for 24 hours,
What was filtered through a 0.2 μm filter was used. The measurement was performed three times, and the average value was defined as the average molecular weight.

The obtained film was subjected to the following evaluation.

[0036] 1) The weight average molecular weight Mw ₂ and a number average molecular weight of weight average molecular weight Mw ₂ and a number average molecular weight obtained film, measured in the same manner as the weight average molecular weight Mw ₁ and the number average molecular weight of the resin of the resin described above did.

2) Appearance Poor appearance such as die lines and bubbles in the center of the obtained film was visually observed. ○ indicates that there was no appearance defect, and X indicates that the appearance defect was observed.

3) Strength The obtained film was bent at 180 °, ○ for those which were bent without any abnormality, and × for those which were broken during bending.
Was noted.

[0039]

[Table 1]

(Examples 3 and 4 and Comparative Examples 3 and 4) A norbornene-based resin (produced by JSR Corporation) having a weight average molecular weight Mw ₁ and a number average molecular weight shown in Table 2 was used at 110 ° C. for 3 hours. After drying, Table 3 (Example 3, Comparative Example 3), Table 4
It was left in the oven at the predetermined temperature shown in (Example 4 and Comparative Example 4), and after a lapse of a predetermined time, the weight average molecular weight was measured again to calculate the molecular weight reduction rate. Here, the molecular weight reduction rate was fixed with respect to time, and was calculated by primary regression analysis.

Next, based on the following equation 1), a function Mw ₃ for predicting a decrease in molecular weight after molding was obtained by regression analysis. Mw ₃ = Mw ₁ −∫aexp (bT) dt 1) The values of a and b are shown in Tables 3 and 4.

On the other hand, the above-mentioned norbornene resin (having a predetermined weight average molecular weight Mw ₁ and a number average molecular weight) is
After drying at 10 ° C. for 3 hours, the mixture was supplied to an extruder having each part having the volume shown in Table 2, and a norbornene-based resin film was obtained in the same manner as in Example 1. The residence time calculated from the volume of each part is shown in Table 5, and the molecular weight reduction amount and the sum total (Mw ₁ -Mw ₃ ), Mw ₃ are calculated from the residence time and the set temperature based on the formula 1). / Mw ₁ and Example 1
Table 2 summarizes the results of the appearance and the strength evaluated in the same manner as in the above.

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

[Table 5]

(Examples 5 and 6, Comparative Examples 5 and 6) A norbornene-based resin film was obtained in the same manner as in Example 3 except that only the polymer filter was considered in the prediction of a decrease in molecular weight, and the residence time in the polymer filter was measured. The molecular weight reduction amount (Mw ₁ -Mw ₄ ), Mw ₄ / Mw ₁ , and the appearance and strength results evaluated in the same manner as in Example 1 were calculated based on the formula (1) from the above and the set temperature. The results are summarized in Table 6.

[0048]

[Table 6]

[0049]

The method for producing a norbornene-based resin film of the present invention 1 is constructed as described above, so that there is no appearance deterioration or strength deterioration of grease, die lines, bubbles, etc. due to thermal deterioration.

Since the method for producing a norbornene-based resin film of the present invention 2 is constituted as described above, even if the weight average molecular weight of the actually obtained film is not measured,
There is no appearance defect such as grease, die line, bubbles, etc. due to thermal deterioration, and no reduction in strength.

Since the method for producing a norbornene-based resin film of the present invention 3 is constituted as described above, the method can be carried out without using a polymer filter or measuring the weight average molecular weight of the actually obtained film. There is no appearance defect such as grease, die line, bubbles, etc. due to thermal deterioration, and no reduction in strength.

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Claims (3)

[Claims] 1. A method for producing a norbornene-based resin film by melt extrusion molding, wherein a ratio between a weight average molecular weight (Mw ₁ ) of the resin before extrusion and a weight average molecular weight (Mw ₂ ) of the film after extrusion is formed. Mw ₂ / Mw ₁ 0.87
To 1.03, a method for producing a norbornene-based resin film. 2. A method for producing a norbornene-based resin film by melt extrusion molding, wherein the weight average molecular weight (Mw ₁ ) of the resin before extrusion molding and the weight average molecular weight of the resin predicted from the temperature history in melt extrusion molding A method for producing a norbornene-based resin film, wherein the ratio Mw ₃ / Mw ₁ to (Mw ₃ ) is 0.87 to 1.03. 3. A method for producing a norbornene-based resin film by melt extrusion using a filtration device comprising a polymer filter, wherein the weight average molecular weight (Mw ₁ ) of the resin before extrusion and the set temperature of the polymer filter are determined. T, when the residence time of the resin in the polymer filter is t, the ratio Mw ₄ / Mw ₁ to the weight average molecular weight (Mw ₄ ) at the temperature T, time t, which is predicted from the change in the molecular weight of the resin, A method for producing a norbornene-based resin film, which is 0.87 to 1.03.