JPH05212722A - Shaping method for methacrylimide containing polymer - Google Patents

Abstract

PURPOSE:To manufacture a molded product of excellent color tone by making water or an organic solvent of given amount contain in a methacrylimide- containing polymer and heat shaping. CONSTITUTION:The subject polymer is composed of methacrylimide unit represented by the formula I of 2-100wt.% and structural unit introduced by an ethylene monomer of 0-98wt.%. In the formula, R represents H or C1-20 aliphatic group, aromatic group or aliphatic hydrocarbon. At the time of heat shaping, it is necessary to make the amount of water content or organic solvent in said polymer 0.2% or more. It is preferable to contain water from the viewpoint of safety, and the water content should preferably be 0.5-3%. Heat shaping means injection molding or extrusion molding. In the case of injection molding, silver streak or the like is possibly generated, if a large amount of water content or the like exists. In the case of extrusion molding, the volatile content should be removed from a vent port of an extruder. The heat shaping mold temperature is preferably set in the range of 260-345 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for imprinting a methacrylimide-containing polymer having an excellent color tone.

[0002]

BACKGROUND OF THE INVENTION Polymers containing methacrylimide are heat resistant,
Since it is excellent not only in weather resistance and mechanical properties but also in transparency, it is rapidly used in lamp lenses, lighting covers, light guide plates, interior and exterior parts for vehicles, and the like. A methacrylimide-containing polymer is known to be obtained by a reaction of a methacrylic polymer with a primary amine or ammonia. For example, JP-A-62-187705 discloses a methacrylic resin in a mixed solvent. A method has been proposed in which a methacrylimide-containing polymer having excellent heat resistance and transparency is obtained by removing a volatile component after reacting a primary amine such as methylamine at a high temperature.

[0003]

However, although the transparency and color tone of the methacrylimide-containing polymer obtained by the above-mentioned method are certainly excellent, molding by heating immediately after the production of the polymer. As compared with the color tone of the product, there was a problem that the color tone of the molded product heat-molded ten days after the production became slightly yellow. One of the causes of the deterioration of the color tone is the absorption of oxygen in the polymer pellets.
Japanese Patent No. 7627 provides a method of keeping a good color tone of a polymer by subjecting the polymer pellet to an oxygen concentration equal to or less than an equilibrium concentration in a specific atmosphere and subjecting it to heat molding. However, this method requires that the polymer pellets be stored in an inert gas atmosphere or a reduced pressure atmosphere, which has some problems in terms of safety and cost.

[0004]

Therefore, the inventors of the present invention have found that the methacrylimide-containing polymer that has been left in the atmosphere for a long time after production or the color tone after hot-drying the polymer by hot air drying is slightly yellow. As a result of diligent study to solve the problem of becoming a large degree at a safe and low cost,
The present inventors have found that the color tone of the polymer after heating and shaping can be favorably maintained by adding water or an organic solvent to the polymer immediately before heating.

The gist of the present invention is to provide a methacrylimide-containing polymer comprising 2 to 100% by weight of a structural unit represented by the following general formula (I) and 0 to 98% by weight of a structural unit derived from an ethylenic monomer. The method for imprinting a methacrylimide-containing polymer is characterized in that the polymer is mixed with water or an organic solvent in an amount of 0.2% or more.

[0006]

[Chemical 1]

The methacrylimide-containing polymer which is the subject of the present invention has the structural unit represented by the above general formula (I), that is,
It is composed of a structural unit derived from a methacrylimide unit and an ethylenic monomer unit. The ethylenic monomer is a methacrylic acid or a methacrylic acid ester or a mixture thereof, or an acrylic acid ester copolymerizable therewith, styrene, a monoethylenic monomer such as α-methylstyrene, and the like. Are methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, benzyl methacrylate and the like, and examples of the acrylate ester include methyl acrylate, ethyl acrylate, Examples thereof include butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, benzyl acrylate and the like. Furthermore, as something other than the methacrylimide unit,
Some of these ethylenic monomers become amides during the imidization reaction are also included.

In the present invention, the effect of the present invention can be obtained if the methacrylimide-containing polymer contains 2% by weight or more of the methacrylimide unit represented by the general formula (I), but 10% by weight is obtained. When it is contained in the above amount, the effect of the present invention becomes greater, and when it is 60% by weight or more, the effect of the present invention becomes remarkable.

In the method of the present invention, it is necessary that the amount of water or organic solvent in the methacrylimide-containing polymer used for heating is 0.2% or more. From the viewpoint of handleability and safety, it is preferable to contain water rather than an organic solvent, and the effect of the present invention becomes remarkable when the water content is 0.5% to 3%. As a method of keeping the amount of water in the polymer in the above range, there is a method of packing the polymer pellets in a closed container together with a certain amount of water, or a method of storing the polymer under an appropriate humidity. In contrast, the amount of water etc. can be kept constant, whereas in the latter, the amount of water in the polymer will fluctuate unless the polymer is stored in a completely conditioned atmosphere, and the color tone after heating will fluctuate. The tendency remains. Such color tone variation may be an unfavorable phenomenon in applications where strict color tone reproducibility is required. The same effect as the present invention can be obtained by the above-mentioned Japanese Patent Laid-Open No. 3-247.
Although it can be obtained by the method of JP-A-627-627, the method of the present invention does not require the treatment of JP-A-3-247627.

In the present invention, drying before heat shaping is not necessary, but rather drying is not preferable in many cases because it reduces the amount of water in the polymer. The heat shaping of the present invention refers to injection molding, extrusion molding and extrusion pelletizing. In injection molding, if a large amount of water or the like is present, silver streak or the like may occur and the appearance of the molded product may be impaired. In the case of shaping with an extruder, it is necessary to remove such volatile components by providing a vent port in the extruder, and the effects of the present invention can be easily obtained.

Although the temperature of the heating and shaping can obtain the relative effects of the present invention at any temperature, it is preferably in the temperature range of 260 to 345 ° C., more preferably 2
It is in the range of 60 to 320 ° C. When the temperature exceeds 320 ° C, the color tone of the obtained polymer is slightly deteriorated, and when the temperature exceeds 345 ° C, the color tone is further deteriorated.

[0012]

The present invention will be described in more detail with reference to the following examples. In the examples, "parts" means "parts by weight". The physical properties in the examples were evaluated by the following methods. (1) Imidization Ratio (Glutarimide Unit Content) The nitrogen content of the polymer was determined by elemental analysis, and the ratio of the glutarimide ring unit weight to the total polymer weight was calculated and expressed in wt%. (2) Yellowness index (YI value) The methacrylimide-containing polymer obtained by extrusion was 10
It was measured in accordance with JIS-K-7103 by using a methylene chloride solution by weight. (3) The yellowness change rate (ΔYIS) was calculated by the following equation. ΔYIS = YIs of re-extruded product-YI of unextruded pellets
S

Production Example 1 70 parts of methyl methacrylate, 24 parts of toluene, 6 parts of methanol, 0.08 part of 1,1'-azobiscyclohexanecarbonitrile, 0.0325 parts of 2,2-azobisisobutyronitrile, n -Once the dissolved oxygen content in the raw material feed liquid consisting of 0.15 parts of octyl mercaptan is less than 1 ppm, a temperature of 110 is passed through a filter for removing fine particles.
3 ℃, the first stirred tank reactor with an internal volume of 20 liters
It was continuously fed at a rate of kg / Hr. The polymerization conversion rate measured immediately after leaving the reactor was 3.75%.
This polymerization liquid was used as a multi-tube heat exchange type second reactor (constituted from 30 straight tubes with an inner diameter of 12.7 mm and a length of 1000 mm).
And was allowed to proceed to a polymerization conversion rate of 95% at a temperature of 125 ° C. Further, this polymerization liquid was mixed with the following imidizing substance and supplied to a stirred tank reactor in the third reaction zone.

On the other hand, the mixed solvent (toluene: methanol = 1: 1 weight ratio) for dissolving and diluting the imidizing substance (methylamine) is adjusted to a dissolved oxygen amount of less than 1 ppm as in the case of the raw material feed solution treatment, and then methylamine is added. 40% by weight
Was fed through the filter at a rate of 1.2 kg / Hr, mixed with the above-mentioned polymerization solution and fed to the third reaction zone. The imidizing substance and the polymerization solution were mixed at 100 ° C. for a residence time of 5 minutes, sufficiently mixed using an in-line mixer, and then supplied to the third reaction zone. The mixed liquid of the polymerization liquid and the imidizing substance was supplied from the lower part of the stirred tank reactor in the third reaction zone (internal volume: 15 liters, temperature: 235 ° C.) to carry out the imidization reaction, and then exited from this reaction zone. The above reaction liquid was supplied to a stirring tank type reactor which serves as an aging reaction zone having an internal volume of 3 liters and a temperature of 235 ° C. The reaction liquid exiting these reaction zones was flushed from the nozzle port into a tank controlled under a reduced pressure of 100 Torr, and the flushed polymer was corrosion-resistant by chrome plating. Supplied above, stainless steel barrel holding 30φ
A twin-screw extruder with a double vent was used to shape it into strands and pelletize. The extruder with double vent has a vacuum degree of 5 mmHg at the vent part, a temperature of 260 ° C, and a temperature of the metering part of 270 ° C.
The die temperature was 255 ° C. The infrared spectrum of the obtained pelletized polymer was measured and the wave number was 1720 cm ^-1.
And 750 cm ⁻¹ showed absorption peculiar to methacrylimide, and it was confirmed to be a methacrylimide-containing polymer. The imidation ratio of the polymer determined by elemental nitrogen analysis was 90%, and the yellowness index YIS was 0.25.

Production Example 2 A methacrylimide-containing polymer having an imidization ratio of 80% was obtained in the same manner as in Production Example 1 except that the amount of the methylamine solution supplied was 1.0 kg / hr. Yellowness index Y of the obtained polymer
The IS was 0.23.

Reference Example 1 Pellets of the methacrylimide-containing polymer obtained in Production Example 1 were stored for 30 days in an air atmosphere at a temperature of about 25 ° C. and a relative humidity of about 60%. Water content after 30 days is about 1%
Met. Next, the pellets are vacuumed at 1 Torr and 120 ° C.
After performing vacuum drying for 72 hours, extrusion molding was performed by a twin-screw extruder (barrel temperature 280 ° C.) having two vent ports. At the time of extrusion, nitrogen gas was blown into the pellet charging port and the two vent ports to make the inside of the extruder a nitrogen atmosphere.
The temperature of the molten methacrylimide-containing polymer resin at the mouth of the extrusion nozzle was about 300 ° C. The yellowness index YIS of the obtained shaped product was 0.30 and ΔYIS was 0.05.

Example 1 About 3% of water was allowed to coexist with the methacrylimide-containing polymer pellets obtained in Production Example 1, and then they were hermetically packaged.
The sealed package was stored as it was for 30 days, and then extruded and heat-molded under the same conditions as in Reference Example 1. Table 1 shows the yellowness index YIS and ΔYIS of the obtained shaped product.

Example 2 The same experiment as in Example 1 was conducted except that about 2% of water was allowed to coexist with the pellet. Table 1 shows YIS and ΔYIS of the obtained shaped product.

Example 3 The pellets obtained in Production Example 1 were treated at a temperature of about 25 ° C. and a relative humidity of about 6
It was stored in a 0% air atmosphere for about 30 days. The water content in the pellet after 30 days was about 1%. The pellets were heat-molded by an extruder in the same manner as in Example 1. Table 1 shows YIS and ΔYIS of the obtained shaped product.

Example 4 Except that about 0.5% of water was allowed to coexist with the pellet.
The same experiment as in Example 1 was conducted. YI of the obtained shaped object
S and ΔYIS are shown in Table 1.

Example 5 The same experiment as in Example 1 was carried out except that about 0.5% of acetone was allowed to coexist with the pellet. Table 1 shows YIS and ΔYIS of the obtained shaped product.

Example 6 The same experiment as in Example 1 was carried out except that approximately 0.5% of methanol was allowed to coexist with the pellet. Table 1 shows YIS and ΔYIS of the obtained shaped product.

Example 7 The same experiment as in Example 1 was carried out except that about 0.5% of toluene was allowed to coexist with the pellet. Table 1 shows YIS and ΔYIS of the obtained shaped product.

Comparative Example 1 The same experiment as in Reference Example 1 was conducted except that the drying time was 6 hours. The YIS and ΔYIS of the obtained shaped product are shown in Table 1, and the yellowness was significantly higher than that in Reference Example 1.

Comparative Example 2 The same experiment as in Reference Example 1 was carried out except that the drying was carried out at 130 ° C. and hot air for 6 hours. YIS and ΔYIS of the obtained shaped product
Is shown in Table 1, which is a high value as in Comparative Example 1.

Reference Example 2 The same experiment as in Reference Example 1 was conducted except that the barrel temperature of the extruder was 300 ° C. and the molten resin temperature at the nozzle port of the extruder was 320 ° C. As shown in Table 2, the yellowness index YIS of the obtained shaped product was 0.35, ΔYIS was 0.10, and the extruded resin temperature was increased to 320 ° C., but in comparison with Reference Example 1. The yellowness value remained slightly higher.

Example 8 Example 1 was repeated except that the barrel temperature of the extruder was 300 ° C. and the molten resin temperature at the nozzle port of the extruder was 320 ° C.
The same experiment was performed. YIS and Δ of the obtained shaped product
YIS is shown in Table 2.

Example 9 Example 3 was repeated except that the barrel temperature of the extruder was 300 ° C. and the molten resin temperature at the nozzle port of the extruder was 320 ° C.
The same experiment was performed. YIS and Δ of the obtained shaped product
YIS is shown in Table 2.

Comparative Example 3 An experiment similar to that of Example 9 was performed, except that drying was performed at 130 ° C. for 6 hours with hot air before extrusion. The YIS and ΔYIS of the obtained shaped product are shown in Table 2, and the yellowness value was significantly higher than that in Reference Example 2.

Reference Example 3 The same experiment as in Reference Example 1 was conducted except that the barrel temperature of the extruder was 320 ° C. and the molten resin temperature at the extrusion nozzle port was 345 ° C. The yellow index YIS of the obtained shaped product is 0.
52 and ΔYIS were 0.27, which were slightly higher than those in Reference Example 1.

Example 10 The same experiment as in Example 1 was carried out except that the barrel temperature of the extruder was 320 ° C. and the temperature of the molten resin at the extrusion nozzle port was 345 ° C. Table 1 shows YIS and ΔYIS of the obtained shaped product.

Comparative Example 4 The same experiment as in Reference Example 3 was carried out except that the drying before extrusion was carried out at 130 ° C. and hot air for 6 hours. YI of the obtained shaped object
S and ΔYIS are shown in Table 2, and the value of yellowness is significantly higher than that of Reference Example 3.

Reference Example 4 The same experiment as in Reference Example 1 was conducted using the pellets obtained in Production Example 2. The yellowness index YIS of the obtained shaped product is 0.28, ΔY
Is 0.05, and dried for a long time under high vacuum and heating,
It can be seen that the resin having a small yellowness change rate can be obtained by performing the low temperature extrusion.

Example 11 The same experiment as in Example 1 was conducted on the pellets obtained in Production Example 2. Table 2 shows YIS and ΔYIS of the obtained shaped product.

Comparative Example 5 The same experiment as in Reference Example 4 was carried out except that the drying before extrusion was carried out at 130 ° C. and hot air for 6 hours. YI of the obtained shaped object
S and ΔYIS are shown in Table 2, and the value of yellowness is significantly higher than that of Reference Example 4.

[0036]

[Table 1]

[0037]

[Table 2]

[0038]

EFFECTS OF THE INVENTION According to the method of the present invention, even if a methacrylimide-containing polymer is heat-molded without a special oxygen removing operation, a polymer having a small yellow tint and a controlled degree of yellowness can be obtained. Since it is obtained, it has an excellent industrial effect.

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[Procedure amendment]

[Submission date] March 5, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction content]

Hereinafter, the present invention will be described in more detail with reference to examples. In the examples, “part” means “part by weight”.
Represents. The physical properties in the examples were evaluated by the following methods. (1) Imidization Ratio (Glutarimide Unit Content) The nitrogen content of the polymer was determined by elemental analysis, and the ratio of the glutarimide ring unit weight to the total polymer weight was calculated and expressed in wt%. (2) Yellowness index (YI value) The methacrylimide-containing polymer obtained by extrusion was 10
Make a solution of methylene chloride in weight% and put it in a 10 mm thick cell.
It was measured with a color difference meter (manufactured by Shimadzu Corporation: UV-2100). (3) The yellowness change rate (ΔYIS) was calculated by the following equation. ΔYIS = YIs of re-extruded product-YI of unextruded pellets
S

[Procedure Amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction content]

Production Example 1 70 parts of methyl methacrylate, 24 parts of toluene, 6 parts of methanol, 0.08 part of 1,1'-azobiscyclohexanecarbonitrile, 0.0325 parts of 2,2-azobisisobutyronitrile, n -Once the dissolved oxygen content in the raw material feed liquid consisting of 0.15 parts of octyl mercaptan is less than 1 ppm, a temperature of 110 is passed through a filter for removing fine particles.
3 ℃, the first stirred tank reactor with an internal volume of 20 liters
It was continuously fed at a rate of kg / Hr. The polymerization conversion rate measured immediately after leaving the reactor was 75% . This polymerization liquid was used as a multi-tube heat exchange type second reactor (inner diameter 1
It was introduced into 30 straight tubes having a length of 2.7 mm and a length of 1000 mm), and the polymerization was advanced at a temperature of 125 ° C. to a polymerization conversion rate of 95%. Further, this polymerization liquid was mixed with the following imidizing substance and supplied to a stirred tank reactor in the third reaction zone.

Claims (5)

[Claims] 1. A structural unit 2 represented by the following general formula (I):
When heat-molding a methacrylimide-containing polymer consisting of ˜100 wt% and a structural unit of 0-98 wt% derived from an ethylenic monomer, the polymer contains water or an organic solvent in an amount of 0.2% or more. A method for imprinting a methacrylimide-containing polymer, comprising: [Chemical 1] 2. The method of molding a methacrylimide-containing polymer according to claim 1, wherein the molding is performed by heating with an extruder. 3. The method for imprinting a methacrylimide-containing polymer according to claim 1, wherein the heating temperature is 260 to 345 ° C. 4. The method for imprinting a methacrylimide-containing polymer according to claim 1, wherein the methacrylimide-containing polymer contains water. 5. The method for imprinting a methacrylimide-containing polymer according to claim 1, wherein the content of water is 0.5 to 3%.