WO1999009105A1

WO1999009105A1 - Glass fiber sizing composition

Info

Publication number: WO1999009105A1
Application number: PCT/US1998/016918
Authority: WO
Inventors: Yong Deng; Charles Cushman
Original assignee: Owens Corning
Priority date: 1997-08-15
Filing date: 1998-08-14
Publication date: 1999-02-25

Abstract

The present invention provides a starch and vinyl amino silane based sizing composition to be used in the manufacture of high strength glass fiber strands. Such glass fibers, or their woven, non-woven or braided form, may be used as reinforcement of concrete, paper tapes, scrims, telecommunication cables, printed wire circuit boards and other composite material where fiber strength is important.

Description

GLASS FIBER SIZING COMPOSITION

This application claims the benefit of U.S. Provisional Application No. 60/055,807 filed on August 15, 1997.

TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION

The present invention provides a starch and vinyl amino silane based sizing composition to be used in the manufacture of high strength glass fiber strands. Such glass fibers, or their woven, non-woven or braided form, may be used as reinforcement of concrete, paper tapes, scrims, telecommunication cables, printed circuit boards and other composite materials where fiber strength is important.

BACKGROUND OF THE INVENTION Sizing compositions are well known and widely used in the manufacture of glass or carbon fibers to improve their processing properties, such as: fiber bundle cohesion, bundling, spreadability, resistance to fuzz formation, fiber smoothness and softness, abrasion resistance and easy and nondestructive unwindability of bobbined fiber bundles. Sizing compositions also affect the physical properties of the composite containing the treated fibers.

The composite industry has been using glass fibers in various forms for reinforcing polymeric matrices, concrete, paper, paper/foil and cables to produce a variety of products. Glass fibers have been used in the form of continuous or chopped filaments, strands and rovings, as well as woven, non-woven and braided fabrics, and meshes and scrims as reinforcements.

Production of glass fibers for the composite market involves attenuation of the glass fibers from molten streams of fiberizable glass material from a bushing or like device connected to a furnace containing molten fiberizable glass material. The glass fibers are attenuated by conventional means such as winders. In the process of producing glass fibers, a chemical composition is applied to them shortly after they are attenuated from molten streams of glass. This chemical composition is typically an aqueous mixture containing one or more starches or non-starch film formers, one or more lubricants and emulsifiers, and optionally, one or more organo functional silanes. This chemical composition or sizing is necessary in order to retard inter filament abrasion of the glass fibers when they are gathered into glass fiber strands. It is also required for the subsequent processing, such as winding, twisting, weaving and braiding, of the glass fibers into the final product. The size composition is designed to further provide hydrolytic stability, moisture resistance, and corrosion resistance as well as to act as a processing aid for handling of the fibers. After application of the sizing, the fibers are then dried either in the package form or in the chopped strand form before they are used as reinforcement.

Attempts for improving the break (tensile) strength of glass fiber strands have been directed toward production of lower yield strands and the addition of greater amounts of organosilanes. Both methods sought to improve the physical characteristics. However, lowering yield raises production costs substantially and the addition of greater amounts of a specific organosilane or combination of organosilanes is effective only within a certain limited range.

Accordingly a need exists for a new sizing composition that raises the break strength of starch-sized glass strands without lowering yield or using a number of organosilanes. This is fulfilled by the composition and process of the invention described below.

All publications, including but not limited to patents and patent applications in this specification are herein incorporated by reference as if each individual publication were individually and specifically indicated to be incorporated by reference herein as though fully set forth.

SUMMARY OF THE INVENTION

The present invention provides a starch and vinyl amino silane based sizing composition that provides high yield glass strands with high strength. The size contains one or more starches and one or more vinyl amino silanes, and, optionally, one or more lubricants and emulsifiers. The composition of the size allows for the glass strand to be utilized in reinforcement applications, such as paper tapes, scrims and telecommunication cables, requiring improved tensile strength.

One embodiment of the starch and vinyl silane based sizing composition of the present invention contains one or more starches which are a high amylose corn starch and hydroxyethylated hybrid corn starch, and one or more vinyl amino silanes. The sizing is applied at temperatures ranging from about 50°C to about 65°C.

In another embodiment, the invention provides a method for controlling and improving the puncture resistance or beach puncture of a composite product. In particular, by application of the sizing composition of the present invention, it is possible to improve the puncture resistance while improving tensile strength.

DETAILED DESCRIPTION AND PREFERRED EMBODIMENTS OF THE INVENTION

The starch and vinyl amino silane based sizing composition of the present invention is comprised of one or more starches, one or more vinyl silanes, and optionally, one or more ionic or nonionic lubricants and emulsifiers.

Any starches known to those skilled in the art may be used. The preferred starches are corn starches and potato starches having an amylose content ranging from about 25% to about 75%. Exemplary starches are nonsynthetic ones selected from the group consisting of a hydroxyethylated 70% amylose corn starch from American Maize with a trade name of Amaize 71 , an acid and cationically modified common corn starch from National Starch & Chemicals with a trade name of CATO 75 and a 55% amylose hybrid com starch from National Starch Chemicals with the trade name HYLON V. The preferred range of starches is from 40 to 70% on a nonaqueous basis.

The vinyl amino silane should be one which reduces the rate of attack by water on glass while increasing the lifetime of the glass/coating interface's resistance to moisture exposure. One of the preferred silanes has a trade name of Z-6032 silane manufactured by Dow Corning®, Midland, Michigan. It is a 40% silane solution in methanol; has a specific gravity of 0.9% at 25°C, a refractive index of 1.395 at 25°C, and a viscosity of 2.2 at 25°C. The chemical formula is

(CH₃O)₃— SiCH₂CH₂CH₂NHCH₂CH₂NHCH₂— θ/— ^CH=CH2— ^HCI

and is designated N-2-(vinyl benzylamino)-ethyl-3-amino propyltrimethoxy silane- monohydrogen chloride. Another preferred silane is Z-6224 silane also manufctured by Dow Corning®. It has a specific gravity of 0.88 at 25°C, a refractive index of 1.388 at 25°C and is the neutralized (chloride-free) version of Z-6032. Preferably the vinyl amino silanes are used in an amount of from about 1 to about 25% percent active ingredient of the sizing composition on a nonaqueous basis. A particularly preferred amount ranges from about 2% to about 10%. Typically, at least one cationic lubricant, one nonionic lubricant and one emulsifier are also present.

Preferred cationic lubricants include stearic ethanolamide (Lubsize K12 commercially available from Alpha/Owens Corning), lubricants disclosed in U.S. Patent No. 3,597,265 (commercially available from Emery Corp. under the trade designation Emerlube 6760 and Emerlube 6717) and a blend of: 30% white oil; 30% polyethylene glycol 400 monopelargonate; 30% POE (3) myristic alcohol; and 10% ethoxylated alkyl amine (Parastat S-2) (commercially available from Emery Corp. under the trade designation Emerlube 7607). Preferably, the lubricant is present in the sizing composition in an amount of from about 2 to about 15 percent on a nonaqueous basis.

Preferred nonionic lubricants are oils and waxes selected from the group consisting of water insoluble vegetable oils and waxes; natural oils primarily unsaturated triglycerides such as corn oil, soya and coconut; hydrocarbon waxes, etc. Emulsifiers may be selected based on the desired HLB (hydrophile-lipophile balance) value which measures the hydrophobic or hydrophilic nature of the substance. The lower the HLB number, the more hydrophobic the material. In a particularly preferred embodiment, vegetable oil and paraffin wax along with polyoxyethylene sorbitan monooleate and octylphenoxy poly(ethyleneoxylol) ethanol are used.

In addition to the above components, other components that are normally added to glass fiber sizing compositions can also be present. For example, the sizing composition of the invention may contain polyethylene glycol as another lubricant.

In the process of the invention, a strand of substantially continuous glass fibers is formed by conventional techniques such as drawing molten glass through a heated bushing to form a multitude of substantially continuous glass fibers and collecting the fibers into a strand. Any apparatus known in the art for producing such fibers and collecting them into a strand can suitably be used in the present invention. Suitable fibers are fibers having a diameter of from about 3 to about 20 microns, and suitable strands contain from about 50 to about 1 ,632 fibers. Preferably, the strands formed in the process of the invention contain from about 100 to about 650 having a diameter of from about 6 to about 13 microns.

The sizing composition can be applied to the glass fibers by any method known to those skilled in the art such as during the formation of the glass fibers or after the glass fibers have cooled to a sufficient temperature to allow the application of the sizing composition. The sizing composition can be applied to glass fibers by applicators having belts, rollers, sprayers, and hot melt applicators.

Preferably the sizing composition is applied by a heated applicator which is capable of applying or metering small amounts of sizing uniformly to a continuous glass strand. The preferred applicators are apron applicators and roll applicators.

The sizing of the present invention may be applied at temperatures ranging from about 40°C to about 70°C. Preferably, the sizing is applied in the range of about 50°C to about 65°C. In a particularly preferred embodiment, the sizing is applied at 60 °C. The sizing may be applied at viscosities ranging from about 4 to about 30 cps. Preferably, the sizing is applied in the range of about 7 to about 15. in a particularly preferred embodiment, the sizing is applied at a viscosity of about 12 cps.

Example I

A sizing composition with a vegetable lubricant was prepared using the following ingredients:

To prepare the size, the vinyl amino silane was prehydrolyzed by adding 0.06 lb of water to the mixture of silane and glacial acetic acid and agitating for one hour. Then, the 25% acetic acid was added to the mixture, followed by 4.29 lb. of water and fast agitation for 0.5 hour. This yielded a 5% vinyl amino silane premix of about pH 4.0, which was subsequently added to the main mix prepared with the rest of the ingredients. This later mix may be prepared in any sequence. A steam jet cooker was used to cook the starches and a homogenizor with a Venturi-type of element was used to prepare the vegetable oil in water emulsion with the emulsifiers. The sizing, once prepared, was constantly agitated with a stirrer, until used or disposed of.

The size was then pumped to a suitable applicator, specifically an apron applicator. The glass fibers were attenuated and allowed to contact the applicator; and the sizing, at about 60°C, was then transferred to the glass. The fibers were gathered and wound onto a forming cake/package. The package was then twisted to yield a G150 yarn (3 micron fibers).

Example II

Another sizing composition was prepared using the following ingredients:

It was prepared as in Example I except that a wax in water emulsion was prepared using a homogenizor and a 3% vinyl amino silane premix was used by adding 7.46 lb of water to the mixture of prehydrolyzed silane and 25% acetic acid, and H110 yarn (10 micron fibers) samples were prepared for testing. Both yarns were made and tested against a corresponding sample without the Z-6032 vinyl amino silane as a control. The mechanical properties were as follows below:

Yarn Tensile (lbs.) control without silane Ex. 1 4.5

Example 1 5.5 control without silane Ex. 2 5.3

Example 2 7.9 Example III

Yarns were tested as follows:

Yarn Average Beach Puncture

Test i Test 2

A no silane 24 27

B Z-6032 vinyl amino silane 33 35

C competition containing silane 28 30

Claims

WHAT IS CLAIMED IS:

1. A starch sizing composition for application to glass reinforcing fibers comprising :

(a) one or more starches having an amylose content ranging from about 55% by weight to about 75% by weight;

(b) one or more vinyl amino silanes; and

(c) one or more waxes.

2. The sizing composition of claim 1 , wherein said vinyl silane is present in an amount effective to provide an increase in the tensile strength of said glass fiber.

3. The sizing composition of claim 1 , wherein said vinyl amino silane is present in an amount ranging from about 1 % to about 25% of the total nonaqueous composition.

4. The sizing composition of claim 1 , wherein said starch is selected from the group consisting of a high amylose corn starch and hydroxyethylated hybrid corn starch.

5. The sizing composition of claim 1 , wherein said starch is present in an amount ranging from about 40 to about 70 percent on a nonaqueous basis.

6. The sizing of claim 1 further including one or more lubricants.

7. The sizing composition of claim 6, wherein said lubricant is cationic and is present in said composition in an amount of from about 2 to about 15 percent on a nonaqueous basis.

8. The sizing of claim 1 further including one or more oils and emulsifiers.

9. A starch sizing composition for application to glass reinforcing fibers made by combining :

(a) one or more starches; (b) neutralized vinyl amino silane;

(c) optionally, one or more waxes, oils and emulsifiers; and

(d) optionally, one or more lubricants.

10. A glass strand having at least a portion of its surface covered with the dried residue of a sizing composition containing the composition of claim 1.

11. A process for manufacturing a glass strand having high break/tensile strength which comprises:

(a) attenuating glass filaments;

(b) coating said filaments with the sizing composition of claim 1 ; and

(c) winding said coated filament onto a rotating cylinder.