JPS6164733A - Diallyl phthalate film and its production - Google Patents

Abstract

PURPOSE:A transparent film excellent in heat resistance, electrical properties and optical properties and suitable for use as, e.g., a protective cover for a polarizing plate of a liquid crystal display element, prepared by curing a film made of a mixture of a diallyl phthalate prepolymer and a radical-polymerizable monomer. CONSTITUTION:20-80pts.wt. diallyl phthalate prepolymer (of a solution viscosity of about 50-130cP, an iodine value of about 50-80, a softening point <=about 130 deg.C and a residual monomer content <=about 5wt%) is mixed with 80-20pts. wt. radical-polymerizable monomer (a mixture of about 100-50wt% mono functional monomer such as vinyl acetate and about 0-50wt% polyfunctional monomer such as divinylbenzene). This mixture is applied to a substrate such as a glass plate, cured by irradiation with, e.g., electron beams, and peeled from the substrate to obtain a transparent film (of a transmittance >=about 88% and a double refractive index <=about 10<-5>).

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a diallyl phthalate film and a method for producing the same.

(Prior art) Giary/I/7 tallate resin has been widely used in electrical products such as glint boards, insulating parts, decorative boards, and paints due to its excellent heat resistance, electrical insulation, and dimensional stability. Being used. However, most of these materials are used as a laminate of phenol paper, nonwoven fabric, glass fiber, etc. and diaryl phthalate resin, or they are used as a base material as a paint. Applications that take advantage of the optical properties of diallyl phthalate resin include molded optical lenses. However, no examples have been found in which a film containing a radically polymerizable monomer and a diallyl phthalate prepolymer as the main components is used.

(Structure and Effects of the Invention) The present inventors have made use of the heat resistance, electrical properties, and optical properties of diallyl phthalate resin while creating an economical and transparent shea! Results of intensive research on IA/7 tallate resin film and its manufacturing method L a) Diallyl phthalate prepolymer, 20
~80 parts by weight b) A film 2 consisting essentially of 80 to 20 parts by weight of a radically polymerizable monomer, a) diallyl phthalate prepolymer, 2
0 to 80 parts by weight b) A method for producing a film characterized by irradiating a mixture consisting essentially of 80 to 20 parts by weight of a radically polymerizable monomer with ionizing radiation is superior overall. This discovery led to the present invention.

These can be obtained by polymerizing one or more of them. As for the polymerization method, thermal bulk polymerization may be performed in the presence of a peroxide such as benzoyl peroxide or methyl ethyl ketone peroxide, or polymerization may be performed in the presence of oxygen without using a catalyst. Furthermore, a diallyl phthalate prepolymer to which oxygen is added by heat or ionizing radiation in the presence of oxygen may be used as a radical polymerization initiator for polymerization. Thereafter, the monomer and prepolymer are separated by 7-alcohol extraction or the like.

Regardless of the polymerization method, the diallyl phthalate prepolymer used in the present invention has a solution viscosity (50% by weight methyl ethyl ketone, 30°C) of 50 to 130 cps, an iodine value of 50 to 8o1, a softening point of 130°C or less, and a residual upper layer. 5
It is sufficient if it is within the range of % by weight or less.

Further, copolymers of diallyl phthalate and triallylisone anurate, triallylne anurate, diethylene glycol bisallyl carbonate, etc. can also be used as the prepolymer of the present invention.

The radically polymerizable monomer is a) monofunctional monomer or (2)
) Any suitable combination of monofunctional monomers and polyfunctional monomers may be used.

The monofunctional monomer has one radically polymerizable group at the end.
Vinyl acetate, vinyl pyridine, vinyl pyridine compounds, acrylic acid, alkyl acrylate, 2-ethylhexyl acrylate, 2-ethylhexyl acrylate, etc.
Hydroquine 1/L/kyl acrylate, ethoxyethoxyethyl acrylate, tetofhydrofurfuryl acrylate, benzyl acrylate, 2-phenoxyethyl acrylate and other 7-cryl V-to compounds, methacrylic acid, methyl methacrylate, 7μ kyl methacrylate,
2-EthylhexS/μ methacrylate, 2-hydroxyalkyl methacrylate, ethquinethyl methacrylate, tetrahydrofurfuryl methacrylate, Alip
Examples include methacrylic compounds such as methacrylate V-meter and grindyl methacrylate.

Examples of polyfunctional monomers include divinylbenzene, neopentyl glycol diacrylate, 1,6-hexane glycol diacrylate, diethyl glycol diacrylate,
Tri ethylene glycol! Resiacrylate, polyethylene glycol diacrylate, pentaerythritol triacrylate, trimethylolpropane trimecrylate, 1,4-gutanedio! Resimethacrylate, Ethyl V glycol A/dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, diallyl butarate, diethylene glycol bisallyl carbonate, triaryl/thiata V-
), triaryl/isocyanurate, and other compounds having two or more radically polymerizable groups are suitable.

As a component of the film, diary phthalate V
Polymer zO ~ 80 parts by weight, radically polymerizable monomer 80
~20 parts by weight is preferred. In addition, the ratio of monofunctional monomer/polyfunctional monomer in the radically polymerizable monomer is 10 by weight.
0-5010-50 is preferable, more preferably 100
~7010~30. Since the diallyl phthalate prepolymer is usually obtained as a solid, it is dissolved in a radically polymerizable monomer to obtain a mixture. When the content of the diaryl phthalate prepolymer increases, the viscosity of the mixture becomes high and the workability of the film forming process becomes poor, and the flexibility of the obtained film decreases. When the content of the diallyl phthalate prepolymer is small, the malleability is improved, but the properties of the diallyl phthalate resin are impaired. Although a solvent is not necessarily required in the present invention, it is also possible to use a solvent such as acetone, tetrahydrofuran, methyl ethyl ketone, methylene chloride, etc. for the purpose of reducing the viscosity of the mixture. However, depending on the final use, the use of a solvent is not necessarily suitable, and agents may be added, but they are not necessarily required in the present invention.

The noacyl phthalate polymer and the radically polymerizable monomer are thoroughly stirred and mixed, and coated onto a support to a predetermined thickness using a known means such as a coater or aggregator.

The support in this case may be anything that allows the film to be easily peeled off after the film is formed, and glass plates, polyester films, Teflon films, release paper, cellophane paper, etc. are suitable.

The mixture coated on the support to a predetermined thickness is cured together with the support. When obtaining a cured film by heat,
It is desirable to use a mixture containing a physical polymerization initiator.

However, heat curing treatment takes a long time, and the storage stability of the mixture is poor due to the radical polymerization initiator.
The disadvantage is that the easily polymerizable radically polymerizable monomer polymerizes before the diallyl phthalate prepolymer is cured, resulting in poor strength of the resulting film. Therefore, the following curing treatment using ionizing radiation provides a uniform and good film in a short time, and since it does not require a radical polymerization initiator, the mixture has excellent storage stability, and is therefore a preferred manufacturing method.

Ionizing radiation refers to X-rays, α-rays, β-rays, and γ-rays.
- This refers to radiation, electron beams, and ultraviolet rays, but electron beams and ultraviolet rays are preferable from the viewpoint of equipment availability, ease of operation, safety, etc. However, treatment with ultraviolet rays requires a photopolymerization initiator, which poses problems regarding the storage stability of the mixture.
Furthermore, in view of the difficulty in polymerizing allyl compounds, electron beams having higher energy than ultraviolet rays are preferable in the present invention.

The irradiation dose of electron beam is l Q Mrad ~1
00 Mrad, more preferably 20 to 50 Mrad. Difficult to cure at doses below 10 Mrad<
If it exceeds 100 Mrad, productivity will be poor. The accelerating voltage varies depending on the thickness of the film, but when producing a film of around 100 μm, it is 100 to 300 KV, more preferably 150 to 200°C.

The irradiation time varies depending on the dose, accelerating voltage, and current, but is usually 0.1 seconds to several seconds.

The present invention is achieved by irradiating the support coated with the mixture with ionizing radiation and then peeling off the cured film from the support.

The film obtained by the present invention has excellent optical customization, a light transmittance of 88% or more, and a birefringence of 10-s or less,
For applications that require a low birefringence index, and because no evaporated components remain in the resulting film, post-processing under vacuum such as vapor deposition, swab-filling, and ion-blating is easy. It is suitable for applications that require processing, such as polarizing plate protective covers for liquid crystal display elements, and protective films for liquid crystal films such as cello discs and compact dinuks.

(Example) The present invention will be explained below with reference to Examples.

Implementation De-11-8 Diallyl orthophthalate prepolymer (iodine value 60
．． 50% by weight methyl ethyl ketone solution viscosity t at 30°C
o cps (number average molecular weight 8850 as calculated from 1m quasi-polystyrene) was thoroughly stirred and mixed with a radically polymerizable monomer in the composition shown in Table 1 (numbers indicate parts by weight), and the mixture was mixed using an aggregator. and coated on a glass plate or polyester film. This sample was heated to 17% in a nitrogen atmosphere with an oxygen concentration of 100 ppm or less.
5KV, 8.6 mA electron beam at 20 Mrad or 3
After irradiation with 0 Mrad and peeling off the cured film from the support, the following evaluations were performed. The evaluation results are shown in Table 2.

The evaluation method will be explained below.

Gel fraction: Calculated from the change in weight of the film after immersing cured lime in acetone and leaving it to stand overnight.

Tensile strength and elongation at break and yield strength and elongation: A film with a distance R20n and @LO#M was pulled on a tensile iron at a speed of 10 ta/min, and each strength and elongation were calculated from the chart.

Total light transmittance: Total light transmittance was measured using a haze meter manufactured by Suga Test Instruments KK.

Birefringence: Using a polarizing microscope and a correction plate Berek compensator (Olympus light "f-H"), the diamond/l/ values a and b of the compensator were measured.

J a -b (/2 f) II E compatible f Ru i
Toooo.

Find f(i) from the table and multiply the value by 0.886.

The value divided by the film thickness T was defined as the birefringence index.

Claims (1)

[Claims] 1. a) Diallyl phthalate prepolymer, 20-80
Film 2 consisting essentially of 80 to 20 parts by weight of b) radically polymerizable monomer, a) diallyl phthalate prepolymer, 20 to 80 parts by weight;
Weight part b) A method for producing a film, comprising irradiating a mixture consisting essentially of 80 to 20 parts by weight of a radically polymerizable monomer with ionizing radiation.