Poly(meth)acrylaimide having improved optical and color properties, particularly under thermal load

A technology of imidization and color, applied in the field of thermoplastics, which can solve the problems of deterioration of optical properties, loss of transparency, etc.

Active Publication Date: 2011-04-06
ROHM G M B H
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a result, various unsaturated structures may be formed, which may cause deterioration of optical properties (especially development of intrinsic color, loss of transparency)

Method used

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  • Poly(meth)acrylaimide having improved optical and color properties, particularly under thermal load
  • Poly(meth)acrylaimide having improved optical and color properties, particularly under thermal load
  • Poly(meth)acrylaimide having improved optical and color properties, particularly under thermal load

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0066] Embodiment 1 (the comparative example that does not add stabilizing agent)

[0067] Polymer analogous transformation reactions, i.e. acyl imidization. 10 kg of PMMA molding compound per hour were introduced into the reactive extruder. In the first part of the mixing zone, there is a feed point for the liquid. 3000 g methylamine / h were fed to this feed point as reaction medium. The average reaction time was 5 minutes at a temperature of 250°C. After the reaction is complete, the reaction mixture is depressurized in the vented extruder, gaseous and volatile fractions are removed, and finally strands are extruded, cooled and cut into pellets.

[0068] The resulting product was injection molded on an Arburg 221 injection molding machine to a series of 65 x 40 x 3 mm test pieces, which were determined for yellowness index, clarity and haze according to DIN 6167 and ISO 14782. The Vicat softening temperature determined according to ISO 306 method B 50 is 172.4°C. Four o...

Embodiment 2

[0074] Embodiment 2 (according to the present invention)

[0075] Addition of organic hypophosphite to finished PMMI pellets

[0076] The procedure of Example 1 was repeated, except that a 10.4% (wt%) methanol solution of benzophosphinic acid (BHPS) was added to the downstream vented extruder at a metering rate of 0.2 kg / h. The metering point is selected for addition to the melt which has been cleaned of volatile and devolatilizable constituents. The final concentration of BHPS in the PMMI molding compound was 3000 ppm. According to Example 1, test pieces were prepared from the pellets obtained and a thermal load was applied at 160° C. for a period of 1000 h. The following results are obtained:

[0077] Example

[0078] Table 2: Thermal storage at 160°C (organohypophosphite free acid)

[0079] time [h]

[0080] It can be seen that good clarity, and lower haze and yellowness index can be achieved by the use of benzophosphinic acid. During thermal storag...

Embodiment 3

[0081] Embodiment 3 (according to the present invention)

[0082] Addition of organic hypophosphite to finished PMMI pellets

[0083] The procedure of Example 2 was repeated, except that an 8.4% (weight %) methanol solution of sodium benzophosphinate was added to the downstream vented extruder at a metering rate of 0.2 kg / h. The final concentration of BHPS sodium salt in the PMMI molding compound was 2200 ppm. The following results are obtained:

[0084] Example

[0085] 3

[0086] Table 3: Thermal storage at 160°C (organohypophosphite sodium salt)

[0087] Duration [h]

[0088] It can be seen that good clarity, and lower haze and yellowness index can also be achieved by the use of sodium benzophosphinate.

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Abstract

The invention relates to a method for the production of molding compounds FM having improved optical and color properties, comprising a polymer PM, which includes units of the formula (I), where R1 and R2 are hydrogen and methyl, and R3 is hydrogen, C1-C18-alkyl, C5-C8-cycloalkyl, C6-C10-aryl, and C6-C10-aryl-C1-C4-alkyl, said groups being substitutable by up to three times with groups selected from the group consisting of C1-C4-alkoxy and halogen, produced in a generally known imidization reaction in a reaction extruder, an amount of one or more phosphorous compounds P having a reducing effect, which amount is effective for color stabilization, being added to the polymer PM after conclusion of the imidization reaction, characterized in that the phosphorous compounds are organic phosphorous compounds OP, selected from the group consisting of the compounds of formula (II), where R4 and R5 are hydrogen or an aromatic 6-member ring independent of each other, which may be substituted up to 5 times with a C1-C4-alkyl and/or C5-C8-cycloalkyl group. Molded bodies obtained according to the method, particularly optical fibers, have a low tendency toward yellowing under thermal load, together with low haze (cloudiness) and stable and high transparency.

Description

technical field [0001] The present invention relates to the preparation, processing and use of heat-distortion-resistant thermoplastics, in particular molding compounds based on imidized polymethylmethacrylate. The invention describes molding compounds which, after processing into shaped bodies, for example for light conductor applications, have high transparency (>90%), low haze (<1%) and Only low yellowness index increases. [0002] More specifically, the invention relates to a process for the preparation of a molding compound according to the preamble of claim 1 . Background technique [0003] Polymers based on imidized polymethyl methacrylates are a special class of thermoplastics which are highly transparent and hereby particularly resistant to thermal deformation. Shaped bodies made of this material can withstand significantly higher temperatures for longer periods of time than shaped bodies made of other highly transparent thermoplastics, such as polymethyl me...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C08K3/00
CPCC08K5/5313C08L33/24
Inventor V·赫列诺夫K·萨多N·梅勒K·舒尔特斯K·阿尔布雷希特
Owner ROHM G M B H
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