WO2014010826A1

WO2014010826A1 - Composite sheet, method for manufacturing same, and flexible substrate including same

Info

Publication number: WO2014010826A1
Application number: PCT/KR2013/004667
Authority: WO
Inventors: 정은환; 김성국; 이우진; 김영권
Original assignee: 제일모직 주식회사
Priority date: 2012-07-12
Filing date: 2013-05-28
Publication date: 2014-01-16
Also published as: KR20140009639A; KR101526002B1; CN104136506A

Abstract

The composite sheet of the present invention comprises a matrix and a stiffener impregnated in the matrix, and has a tanδ value (tanδ = G"/G'), which is the ratio of the loss modulus (G") and the storage modulus (G'), of about more than 0 and about less than 0.05. The composite sheet has a tanδ value in a certain range, and the rate of defects which can arise during high temperature processing during substrate manufacture can be reduced in order to impart flexibility, thermal resistance, and, especially, good optical qualities.

Description

Composite sheet, manufacturing method thereof, and flexible substrate comprising same

The present invention relates to a composite sheet, a method for manufacturing the same, and a flexible substrate including the same.

The glass substrate is excellent in heat resistance and transparency, and has a low coefficient of linear expansion. Therefore, glass substrates have been widely used as liquid crystal display elements, substrates for organic EL display elements, color filter substrates, solar cell substrates, and the like. However, the glass substrate is limited in thickness and weight reduction of the liquid crystal display due to the thick thickness and heavy weight, and has a problem in that it is vulnerable to impact resistance. In addition, the brittleness of the glass material makes it unsuitable for use as a substrate for display.

Accordingly, a flexible substrate made of a plastic optical film material has been spotlighted as a material to replace a conventional glass substrate. Flexible substrates have properties that are well suited for next-generation display devices such as liquid crystal displays, organic ELs, and e-paper.

Recently, materials such as polyethylene terephthalate (PET), polyether sulfone (PES), polyethylene naphthalate (PEN), polyarylate (PAR), polycarbonate (PC), and polyimide (PI) are used as plastic substrates. . However, these materials have a problem that the thermal expansion coefficient is considerably high, causing warpage or disconnection of the product. Polyimide-based resins have a relatively low coefficient of thermal expansion, but the problem is pointed out that they are not suitable as substrate materials due to their very low transparency and high birefringence and hygroscopicity.

In order to solve this problem, Japanese Laid-Open Patent Publication No. 2004-51960 discloses an alicyclic epoxy resin containing an ester group, a bisphenol A type epoxy resin, an acid anhydride curing agent, and a transparent composite optical sheet made from a catalyst and a glass fiber cloth. . Japanese Unexamined Patent Application Publication No. 2005-146258 discloses a transparent composite optical sheet made from an alicyclic epoxy resin containing an ester group, an epoxy resin having a dicyclopentadiene skeleton, an acid anhydride curing agent, and a glass fiber cloth. Japanese Laid-Open Patent Publication No. 2004-233851 discloses a transparent substrate made of a bisphenol A epoxy resin, a bisphenol A novolac epoxy resin, an acid anhydride curing agent, and a glass fiber cloth. However, the above patents have a disadvantage in that stress is generated between the fiber and the resin matrix, thereby causing breakage and deteriorating display performance due to large optical anisotropy. Acryl-based and epoxy-based resins used in the conventional glass fiber composites have excellent refractive index but have problems in flexibility and heat resistance.

It is an object of the present invention to provide a composite sheet and a method of manufacturing the same, in which cracks do not occur and defects at the interface between the reinforcement and the matrix do not occur.

Another object of the present invention is to provide a composite sheet having excellent flexibility, transparency and heat resistance, and a method for producing the same.

Another object of the present invention is to provide a composite sheet and a method for manufacturing the same, which can be used for a flexible substrate by improving the defects of materials that may occur in a high temperature process during substrate fabrication.

One aspect of the invention relates to a composite sheet. The composite sheet is a matrix; And a reinforcing material impregnated in the matrix, wherein the tanδ value (tanδ = G ″ / G ′), which is the ratio of the loss modulus G ″ and the storage modulus G ′, is greater than about 0 and less than or equal to about 0.05.

The composite sheet may have a storage modulus measured at 100 ° C. of about 0.1 to 5.0 MPa.

The composite sheet may have a haze of about 15% or less after heat treatment at 220 ° C. for 2 hours.

The matrix may be a crosslinked silicone rubber. .

The reinforcing material may include one or more selected from the group consisting of glass fiber cloth, glass fibric, glass nonwoven fabric, and glass mesh.

Another aspect of the invention relates to a method for producing a composite sheet. The method includes impregnating and curing a reinforcing material in a composition for a matrix comprising siloxane to adjust the tan δ value to greater than about 0 and up to about 0.05.

Another aspect of the present invention relates to a flexible substrate including the composite sheet.

The present invention does not generate cracks and defects at the interface between the reinforcing material and the matrix, and is excellent in flexibility, transparency, and heat resistance, and can improve defects of materials that may occur in the high temperature process in manufacturing the substrate. The present invention has the effect of providing a composite sheet and a method for producing the composite sheet which can be suitably used.

1 is a cross-sectional view of a composite sheet according to an embodiment of the present invention.

1 schematically shows a cross section of a composite sheet according to one embodiment of the invention. According to FIG. 1, the composite sheet 10 of the present invention has a structure in which a reinforcing material 2 is included in a matrix 1. According to one embodiment, the reinforcing material 2 may be included in a layer structure, but is not limited thereto. The reinforcing material 2 may be impregnated in the matrix as a support and present therein. Although not shown in the drawings, the reinforcement 1 may be dispersed in the matrix 1 or impregnated in a woven form, or may be impregnated with the matrix 1 arranged in a uni-direction. The reinforcement 2 may be formed of a single layer or a plurality of layers.

Composite sheet of the present invention is a matrix; And a reinforcing material impregnated in the matrix, wherein the tan δ value can be greater than about 0 and up to about 0.05. In the present invention, the tanδ value is a ratio of the loss modulus and the storage modulus, and can be obtained through a formula of tanδ = G ″ (loss modulus) / G ′ (storage modulus). The loss modulus and storage modulus are Rheometer (Anton Paar, Physica). MCR501), measured at 100 ° C under strain 0.5 (%) and frequency 10 (1 / s), if tanδ exceeds 0.05, high temperatures of about 220 ° C during substrate fabrication. In addition to a significant increase in haze in the process, cracks may occur in the substrate, preferably tanδ is from about 0.001 to about 0.045, more preferably from about 0.005 to about 0.04, most preferably tanδ is from about 0.01 to About 0.03.

The matrix may be a crosslinked silicone rubber.

In one embodiment, the silicone-based rubber may include a polyorganosiloxane resin including a unit of Formula 1 below.

[Formula 1]

(Wherein R and R 'are the same as or different from each other, a hydrogen atom, a substituted or unsubstituted C1-C20 alkyl group, a substituted or unsubstituted C2-C20 alkenyl group, a substituted or unsubstituted C2-C20 alkynyl group, Substituted or unsubstituted C1-C20 alkoxy group, substituted or unsubstituted C3-C30 cycloalkyl group, substituted or unsubstituted C3-C30 cycloalkenyl group, substituted or unsubstituted C3-C30 cycloalkynyl group, substituted or unsubstituted C6-C30 aryl group, a substituted or unsubstituted C6-C30 aryloxy group, n may be an integer of 2 to 1000)

As used herein, "substituted" means hydrogen, halogen atom, hydroxy group, amino group, carbonyl group, thiol group, ester group, ether group, carboxyl group or salt thereof, sulfonic acid group or salt thereof, phosphate group or salt thereof, carbon number An alkyl group of 1-20, an alkenyl group of 2-20 carbon atoms, an alkynyl group of 2-20 carbon atoms, an alkoxy group of 1-20 carbon atoms, an aryl group of 6-30 carbon atoms, an aryloxy group of 6-30 carbon atoms, 3-carbon atoms It means a cycloalkyl group of 30, a cycloalkenyl group of 3-30 carbon atoms, a cycloalkynyl group of 3-30 carbon atoms, or a combination thereof.

Preferably, R and R 'may be a C1-C10 alkyl group, a C2-C10 alkenyl group, or a C6-C10 aryl group.

The weight average molecular weight of the silicone rubber may be about 1,000 ~ 100,000 g / mol /. Within this range, the ease of synthesis and the mechanical properties after curing of the matrix resin in the composite sheet can be expected. Preferably about 1,000 to 50,000 g / mol. In addition, the silicone-based rubber may have a viscosity of about 100cps to about 10,000cps at 25 ℃. It may have excellent flatness, impregnation and processability in the above range.

The glass transition temperature of the silicone rubber may be about -150 ℃ to about 30 ℃. Preferably it may be about -100 ℃ ~ 20 ℃, more preferably about -80 ℃ ~ 0 ℃. In the above range, it has the advantage of excellent flexibility and rigidity and a small coefficient of thermal expansion.

In another embodiment, the matrix together with the silicone rubber is styrene-butadiene rubber (SBR), butadiene rubber, isoprene rubber, chloroprene rubber, neoprene rubber, ethylene-propylene-diene terpolymer, styrene-ethylene-butylene- Styrene (SEBS) block copolymer, Styrene-ethylene-propylene-styrene (SEPS) block copolymer, Acrylonitrile-butadiene rubber (NBR), hydrogenated nitrile rubber (NBR), Flori It may further comprise one or more selected from the group consisting of fluorinated rubber, and plasticized polyvinylchloride rubber.

The reinforcing material may include at least one member selected from the group consisting of glass fiber cloth, glass fiber, glass nonwoven fabric, and glass mesh, for example, glass fiber cloth) can be used.

The reinforcement may have a refractive index difference of about 0.01 or less from the matrix. Within this range, it may have excellent transparency and light transmittance. Preferably, the difference between the matrix and the refractive index may be about 0.0001 to 0.007.

In the composite sheet of the present invention, the matrix: reinforcement material may be included in a weight ratio of about 70:30 to about 95: 5, preferably about 80:20 kPa to about 90:10. Within this range, the physical properties of the composite sheet that can be used as a flexible substrate can be possessed.

The thickness of the composite sheet of the present invention may be about 15㎛-200㎛. In the above range, it can be used as a composite sheet for flexible substrate applications.

Such a composite sheet of the present invention is to prepare a composition for a matrix comprising a vinyl group-containing siloxane, a crosslinking agent, a catalyst and an inhibitor; And it can be prepared by impregnating and curing the reinforcing material in the composition for the matrix.

The vinyl group-containing siloxane is a siloxane containing a vinyl group at the end, preferably about 0.1 to 10.0 mol%. In the above range, the curing efficiency is high, and may have rubbery physical properties after curing. In embodiments, the vinyl group-containing siloxane may have a weight average molecular weight of about 10,000 to 50,000 g / mol. It is easy to mix in the above range, there is an advantage in the impregnation and processability.

The crosslinking agent can use the crosslinking agent normally used in manufacture of the composite sheet for flexible substrates. For example, polyorganosiloxanes having Si—CH 3 and Si—H can be used. Preferably Si-H terminal siloxane or the like may be used. The Si-H terminal siloxane may have a weight average molecular weight of about 500 ~ 10,000 g / mol. It is easy to mix in the above range and excellent in the curing efficiency, it has the advantage of excellent physical properties after curing. The crosslinking agent may be included such that the molar equivalent ratio of the number of moles of Si—H of the crosslinking agent to the number of moles of the C 2 -C 20 alkenyl group of the silicone rubber is about 1.0 kPa or more, preferably about 1.0 kPa to about 1.3.

The catalyst may be a catalyst commonly used in the manufacture of a composite sheet for a flexible substrate. For example, as the platinum-based or rhodium-based catalyst, a complex of platinum and an organic compound, a platinum and vinylated organosiloxane complex, a rhodium and an olefin complex, and the like can be used. Specifically, a vinylalkylsilane platinum complex containing a Karstedt catalyst, platinum black, platinum chloride, chloroplatinic acid-olefin complex, chloroplatinic acid-alcohol coordination compound, or a mixture thereof can be used. The catalyst may be included in the weight of metal in an amount of about 2 to about 2000 ppm, preferably about 5 to about 500 ppm, relative to the rubber-based compound.

The inhibitor can cure the matrix at high temperatures by inhibiting the action of the catalyst at about 25 ° C. and no inhibitory action during the high temperature curing process.

The inhibitor may be used an inhibitor commonly used in the manufacture of a composite sheet for a flexible substrate. For example, inhibitors include acetylenic alcohols including dimethyl-1-hexyn-3-ol, pyridine, phosphines, organic phosphites, unsaturatedamides, dialkylcarbonylates, dialkylacetylenedicarboxylates, alkylated Maleate, diallyl maleate, or mixtures thereof. The inhibitor may be included at about 100 ppm to about 2500 ppm relative to the rubber compound.

A mixture of the catalyst and the inhibitor may be included in an amount of about 0.01 wt% to about 1 wt% based on the rubber compound. Within this range, the catalytic action can be sufficiently exhibited. Preferably, about 0.05 to about 0.2% by weight.

In the present specification, 'impregnation' may include that the reinforcing material is formed in a single layer or a multi-layer structure in the matrix.

The curing may be performed at about 40 ° C. to about 100 ° C., preferably at about 50 ° C. to about 90 ° C., for about 0.1 minutes to about 5 hours, preferably for about 30 minutes to about 2 hours and 30 minutes. Within this range, the surface flatness can be increased while ensuring sufficient curing of the matrix and the reinforcing material.

Specifically, the composition for a matrix may be impregnated with a reinforcing material, then sandwiched between the release-treated films, laminated, and cured.

The curing is adjusted so that the tan δ value is in the range of greater than about 0 and less than or equal to about 0.05. Crack does not occur in the tan δ range and defects at the interface between the reinforcement and the matrix do not occur. Tanδ value of the present invention can be adjusted according to the structure and ratio of the siloxane and the crosslinking agent used as a matrix, the content of the crosslinking agent, curing conditions and the like.

The composite sheet prepared as described above may have a storage modulus measured at 100 ° C of about 0.1 to 5.0 MPa, preferably about 0.5 to 2 MPa, for example, about 0.6 to 1.5 MPa.

The composite sheet has a haze of about 15% or less after heat treatment at 220 ° C. for 2 hours, for example, about 0.1 to 14%, preferably about 0.5 to 10%, more preferably about 0.7 to 7%, most preferably About 0.7-5%.

In another embodiment, the composite sheet may further include a smooth layer, a gas barrier layer, or the like on at least one surface. These forming methods can be easily formed by those skilled in the art to which the present invention pertains.

In another aspect of the present invention, the flexible substrate and the display device including the same may include the composite sheet. Flexible substrates are used for displays or optical devices such as substrates for liquid crystal display devices (LCDs), substrates for color filters, substrates for organic EL display devices, substrates for solar cells, substrates for touch screen panels, and the like. It is available.

Hereinafter, the configuration and operation of the present invention through the preferred embodiment of the present invention will be described in more detail. However, this is presented as a preferred example of the present invention and in no sense can be construed as limiting the present invention.

Details that are not described herein will be omitted since those skilled in the art can sufficiently infer technically.

Example

Specifications of the specific components used in the following Examples and Comparative Examples are as follows.

(a) Vinyl group-containing siloxane: Synthesis was performed using phenylmethyl dimethoxy siloxane (PMDMS), dimethyl dimethoxy siloxane (DMDMS) and vinyl trimethoxy siloxane (VTMS). The weight ratio of (PMDMS + DMDMS): VTMS was maintained at 95: 5. 900 g of PMDMS, 615 g of DMDMS, and 60 g of VTMS were weighed and then hydrolyzed under deionized water / KOH at 70 ° C. for 1 hour. The reaction was continued at 90 ° C., and toluene and water were added to lower the temperature to 25 ° C. and washed with water. 300 g of Vi-MM (1,1,3,3, -tetramethyl-1,3-divinyl disiloxane) was added and end-capped at 50 ° C. for 5 hours, washed at 25 ° C., and then the solvent was removed to remove the silicone rubber PDMS. Resin (polyorganosiloxane resin which has a phenyl group, a methyl group, and a vinyl group) was manufactured. The viscosity at 25 ° C. of the prepared PDMS resin was 500 cps. Viscosity was measured by Viscometer (Brookfield) at 25 ° C. Two kinds of resins having different contents of PMDMS and DMDMS were synthesized for refractive index matching, and the molecular weight (Mn) of vinyl PDMS after synthesis was 10,000 g / mol.

(b) Reinforcement material: Glass fiber cloth (D-glass cloth, Owen corning) was used.

(c) crosslinking agent

(c1) Si-H terminated PDMS: Synthesis was performed using phenylmethyl dimethoxy siloxane (PMDMS) and dimethyl dimethoxy siloxane (DMDMS). Endcapping was performed using H-MM (1,1,3,3-tetramethyl-disiloxane) in the same manner as the above-described Vinyl PDMS. The molecular weight (Mn) of the Si-H terminated PDMS after the synthesis was 2,000 g / mol.

(c2) HMS-991 (Gelest) was used.

(d) Catalyst #: A Karstedt catalyst (PT-CS-1.8CS, Umicore) was used.

(e) Inhibitor: surfynol was used.

Example 1

The vinyl group-containing siloxane (a), Si-H terminated PDMS (c1) and HMS-991 (c2) were blended in a molar ratio of 1: 1: 0.1, and the catalyst (d) and the inhibitor (e) were added thereto, followed by stirring. 10 g of the glass fiber cloth (b) on the release-treated film was poured and then degassed under vacuum. The degassed sample was placed between the release-treated film and the glass, followed by laminatation at a pressure of 0.1 Mpa, and cured at 50 ° C. for 2 hours to prepare a final composite film.

Example # 2

The vinyl group-containing siloxane (a), Si-H terminated PDMS (c1) and HMS-991 (c2) was carried out in the same manner as in Example 1 except for blending in a molar ratio of 1: 0.8: 0.3.

Example # 3

The vinyl group-containing siloxane (a), Si-H terminated PDMS (c1) and HMS-991 (c2) was carried out in the same manner as in Example 1 except for blending in a molar ratio of 1: 0.5: 0.6.

Comparative Example 1

The same procedure as in Example 1 was performed except that the vinyl group-containing siloxane (a), Si-H terminated PDMS (c1), and HMS-991 (c2) were mixed in a molar ratio of 1: 0.1: 1.

Comparative Example 2

The same procedure as in Example 1 was carried out except that the vinyl group-containing siloxane (a) and HMS-991 (c2) were mixed in a molar ratio of 1: 1.1.

With respect to the composite sheet prepared in Examples and Comparative Examples, the following physical properties were evaluated and the results are shown in Table 1.

Property evaluation method

(1) storage modulus and 　 Loss modulus: Rheometer (Anton Paar, Physica MCR501) using a device, strain was measured at 100 ℃ under conditions of 0.5 (%), frequency 10 (1 / s). Jig used a diameter of 50mm diameter of 1 °, the measurement gap was applied to 102μm.

(2) tan δ: The storage modulus (G ′) and loss modulus (G ″) were measured, respectively, and then calculated by G ″ / G '.

(3) HAZE: Measured by a HAZE meter (Nippon Denshoku, NDH2000). It was measured for each of the samples prepared initially and the samples after the heat treatment 220 ° C_2hr.

(4) Crack: It was measured in the reflection mode by an optical microscope. It was measured for each of the samples prepared initially and the samples after the heat treatment 220 ° C_2hr.

×: none, △: partially present, ○: present

Table 1

	Mechanical property		Initial impregnation sample		After 220 ℃ _2hr heat treatment
	G '(Mpa)	tanδ	HAZE (%)	Crack	HAZE (%)	Crack
Example 1	0.8	0.02	2.8	×	3.0	×
Example 2	0.7	0.03	2.7	×	4.6	×
Example 3	0.8	0.05	2.9	×	13.3	△
Comparative Example 1	1.1	0.11	3.0	×	58.0	○
Comparative Example 2	1.0	0.15	2.6	×	65.4	○

As shown in Table 1, Examples 1 to 3 having a tan δ value greater than about 0 and less than or equal to about 0.05 maintained low haze after heat treatment, and it was confirmed that almost no cracks were found. On the contrary, in Comparative Example 1-2 having a tanδ value exceeding 0.05, the haze increased sharply after heat treatment, and it can be seen that cracks occurred.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and can be manufactured in various forms, and a person of ordinary skill in the art to which the present invention pertains has the technical idea of the present invention. However, it will be understood that other specific forms may be practiced without changing the essential features. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive.

Claims

matrix; And

A reinforcing material impregnated in the matrix;

And a tanδ value (tanδ = G ″ / G ′), which is a ratio of the loss modulus (G ″) and the storage modulus (G ′), greater than about 0 and less than or equal to about 0.05.
The composite sheet of claim 1, wherein the composite sheet has a storage modulus measured at 100 ° C. of about 0.1 to 5.0 MPa.
The composite sheet of claim 1, wherein the composite sheet has a haze of about 15% or less after heat treatment at 220 ° C. for 2 hours.
The composite sheet of claim 1, wherein the matrix is a crosslinked silicone rubber.
The composite of claim 1, wherein the reinforcing material comprises at least one member selected from the group consisting of glass fiber cloth, glass fibric, glass nonwoven fabric, and glass mesh. Sheet.
A method for producing a composite sheet comprising impregnating and curing a composition for a matrix comprising a siloxane to harden the tan δ value by more than about 0 to about 0.05 or less.
A flexible substrate comprising the composite sheet of any one of claims 1 to 5.