JPH0248439A - Glass fiber bundle and production of fiber-reinforced resin form using same - Google Patents

Abstract

PURPOSE:To obtain the title FRP with small mechanical strength drop-off after boiling or after repeated stress application by specifying, in a continuous glass fiber bundle treated with an epoxy resin-contg. collecting agent, the epoxy equivalent of the epoxy resin extracted from said fiber bundle. CONSTITUTION:The title glass fiber bundle is obtained by treating glass fiber with an epoxy resin-contg. collecting agent followed by drying, being <=600 in the epoxy equivalent of epoxy compound in a solution produced by extracting for one hour under reflux 20g of said bundle with 25ml of dioxane. Furthermore, the solid content of the above solution is pref. 0.02-0.5g. The residual amount of the epoxy ring in said fiber bundle is closely related to the performance such as mechanical strength of the objective FRP; the greater the former is, the more the latter is improved. Therefore, the objective fiber bundle for FRP of high mechanical strength can be obtained by specifying the composition of the collecting agent and the drying conditions for said fiber bundle so as to be <=600 in the epoxy equivalent of the above-mentioned solution.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a glass fiber bundle suitably used for manufacturing fiber reinforced resin (FRP) and a method for manufacturing FRP.

[Prior art] Glass fiber bundles (strands) obtained by applying a sizing agent to glass fibers pulled out from a lashing, converging, and drying are FRP.
Widely used in the production of

The components of the sizing agent are selected depending on the purpose of use of the strand, and sizing agents using epoxy resin as a film forming agent are used for forming strands for high-strength FRP.

FRP, which requires high strength, is manufactured by using long strands as reinforcing fibers, impregnating these strands with liquid thermosetting resin, and curing the resin while keeping the strands under tension. .

As methods for manufacturing such high-strength FRP, pultrusion molding method and filament winding method (FW method) are known.

[Problems to be solved by the invention] The performance required of high-strength FRP has become increasingly severe in recent years, and products with high strength and small strength loss after boiling tests or when subjected to repeated stress are needed. is requested.

The strength improves as the content of reinforcing fibers in FRP increases, or if the content of reinforcing fibers increases, the impregnation of the liquid thermosetting resin tends to become uneven.

In addition, the strength of FRP can be improved by using special fibers with high strength such as carbon fibers and aramid fibers as reinforcing fibers.
It is more expensive than glass fiber, which is commonly used for FRP, and its uses are restricted due to price.

The present invention uses glass fiber bundles (strands) and strands that provide FRP that has high strength and exhibits a small decrease in strength after a boiling test or when subjected to repeated stress. The objective is to provide a method for obtaining FRP with a small decrease in strength when subjected to repeated stress.

[Means for Solving the Problems] In order to achieve the above object, in the present invention, FRP
As a reinforcement am, a long glass fiber bundle is prepared by manually focusing and drying a sizing agent containing an epoxy resin on glass fibers, and the glass fiber bundle is contained in a solution obtained by extracting 20 gr of glass fiber bundle under reflux for 1 hour using 25 ml of dioxane. A glass fiber bundle in which the epoxy equivalent of the epoxy compound contained is 600 or less, and preferably the solid content of the solution is 0.02 to 0.5 gr, more preferably satisfying the above conditions, and
The absorbance of the epoxy group near 916 cm-'' in the infrared absorption spectrum of the solution extracted by ultrasonically cleaning 50 gr of glass fiber bundle with 300 ml of chloroform for 2 hours and 82
The absorbance of aromatic adjacent 2H near 0 cm-' is A, respectively.
A long glass fiber bundle is obtained by using a glass fiber bundle whose A/B ratio is 0.2 or more when B is used, and by manually focusing a sizing agent containing an epoxy resin on the glass fiber bundle and drying it. The epoxy backing layer of the epoxy resin contained in the solution obtained by extracting 20 gr of glass fiber bundles using dioxane 25 + wJl under reflux for 1 hour is 600 or less, and preferably the solid content of this solution is 0.02 to 0.5 gr. A fiber-reinforced resin body is manufactured by impregnating a long glass fiber bundle with a liquid thermosetting resin and curing the glass fiber bundle under tension, or more preferably, a fiber-reinforced resin body that satisfies the above conditions. , and the absorbance of the epoxy group near 916 cm-' and the aromatic adjacent 2H near 820 CI-' of the infrared absorption spectrum of the solution extracted by ultrasonically cleaning 50 gr of this glass fiber bundle with 300 ml of chloroform for 2 hours.
Impregnating a long male bundle of glass with a liquid thermosetting resin in which A/B is 0.2 or more when the absorbance of A and B are respectively, and hardening the glass fiber bundle under tension. An Fa male reinforced resin body is manufactured by the following steps.

Next, the present invention will be explained in more detail.

The present inventor has aimed to further improve the tensile strength, shear strength, and other properties of high-strength FRP obtained using strands using epoxy resin as a sizing agent, and to improve the strength after a boiling test or when subjected to repeated stress. As a result of numerous experiments, we have obtained the knowledge of a method to obtain FRP with minimal deterioration.

(1) The epoxy rings of the epoxy resin contained in the stranood obtained by manually binding a sizing agent (referred to as a wood sizing agent) containing an epoxy resin as a film forming agent may be damaged by the action of heat during heating and drying, or Easily ring-opened by reaction with other components in the sizing agent.

(2) Amount of epoxy rings remaining in the strand and FRP
There is a close relationship between the strength and other performances of FRP, and the greater the residual amount of epoxy rings, the better the strength and other performances of FRP tend to be.

(3) The present inventor further researched the relationship in (2) above and found the following.

(1) Suitable results can be obtained by determining the composition of the sizing agent and drying conditions for the strands so that the epoxy equivalent of a solution obtained by extracting 20g of strands with 25ml of dioxane under reflux for 1 hour (hereinafter referred to as the extract) is 600 or less. What you get.

(2) The composition of the sizing agent is such that the solid content contained in the dioxane extract is 0.02 to 0.5 gr;
High-strength FRP can be produced by setting the drying conditions for the strands.
To obtain a strand more suitable for use as a strand.

(3) Furthermore, the above conditions are satisfied, and the glass fiber bundle is 50g.
916 c of the infrared absorption spectrum of the solution extracted by ultrasonically cleaning r with chloroform 300 nJ1 for 2 hours.
When the absorbance of the epoxy group near m-" and the absorbance of the aromatic adjacent 2H near 820 cm-" are respectively A and B, A
A more suitable result can be obtained by determining the composition of the present sizing agent and the drying conditions of the strand so that /B is 0.2 or more.

The present invention is a new proposal based on the above knowledge.

Next, the present invention will be explained in more detail.

The strand according to claims 1 and 2.3 (hereinafter referred to as the present strand) can be manufactured as follows.

As the epoxy resin to be contained in the present sizing agent, bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, phenol borac type epoxy resin, alicyclic epoxy resin, etc. can be suitably used.

In addition, the epoxy resin has an epoxy equivalent of 150 to 600.
Preferably, it is appropriate to use one with a molecular weight of 190 to 500.

Further, the content of the epoxy resin in the present sizing agent is suitably 0.1 to 10 wt%, preferably 0.5 to 5 wt% in terms of solid content.

The sizing agent preferably contains a lubricant, a coupling agent, etc. in addition to the epoxy resin, and can also contain a film forming agent other than the epoxy resin.

Suitable lubricants include higher fatty acid esters, polyethylene glycol, etc., γ-aminopropyltriethoxysilane and the like are suitable as a bubbling agent, and polyester resins, polyurethane resins, etc. are suitable as film forming agents other than epoxy resins. .

The amount of this sizing agent is 0.0% as a solid content relative to glass fiber.
It is appropriate to set it at 1 to 5 wt%, preferably 0.2 to 2 wt%.

Glass fiber bundle pulled out from bushing The agent is manually concentrated and then dried.

As mentioned above, the epoxy equivalent in the dioxane extract is 600 or less, preferably 500 or less, and the solid content in the extract is preferably 0.02 to 0.5 gr, particularly preferably 0.05 to 5 gr. 0.2 gr, and also satisfies the above conditions, and the epoxy group near 916 cm-' in the infrared absorption spectrum of the solution extracted by ultrasonically cleaning 50 gr of this glass fiber bundle with 300 ml of chloroform for 2 hours. The drying conditions and the composition of the sizing agent are determined so that A/B is 0.2 or more, where A and B are the absorbance of 2H near 820 cm and the aromatic adjacent 2H near 820 cm-', respectively.

The method for measuring absorbance is as follows.

In the drawing [a graph showing an infrared absorption spectrum with the horizontal axis as the wave number (cm-'') and the vertical axis as the transmittance], the absorbance of the epoxy group peak near 916 cm-'' is indicated by A', and the absorbance is indicated by B'. Aromatic neighbor 2 near 820 cm−1
Obtain the absorbance B of the H peak from the graph. The line m, which is the standard for determining absorbance A, is 980 c+
Spectral valley 1 near +-' and 880 an-'
, 2 (places with high transmittance), and the line n, which is the standard when calculating B, is 880 cm-
A straight line connecting the valleys 2 and 3 near '' and 780 cm-' is adopted. Absorbance A.

B is determined as follows using lengths a, b, c, and d.

dA=log-B=log-3c For extraction with dioxane, strand 20gj is
Preferably, the mixture is cut into pieces of about 2 to 3 cm, placed in a flask, poured with 25 ml of dioxane, and the extracts are brought to a boil using a reflux condenser. The time required for extraction is set as 1 hour.

For extraction with chloroform, cut 50 gr of strands, preferably into 2-3 cm pieces, place them in a beaker, pour in 300 m of chloroform, and heat the flask to 40 kH.
z, Extract by immersing in a water tank equipped with a 50W ultrasonic transmitter. The extraction time is set as 2 hours.

At this time, it is appropriate to cover the top of the beaker with aluminum foil or the like to prevent evaporation and escape of chloroform.

Suitable conditions for obtaining a glass fiber bundle that satisfies the conditions described in h. The smaller the content of the glass fibers, the more favorable the results, that is, the glass fiber bundles that also satisfy the conditions of claims 2 and 3 can be obtained.

(1) Drying at low temperature and shortening drying time.

In order to achieve the above objective, it is important to increase the drying rate.

To this end, it is effective to keep the humidity of the drying atmosphere low, to forcefully circulate the atmosphere in the drying oven, and to increase the contact area between the strands and the atmosphere.

In order to increase the contact area, when the strands are wound into a cylindrical shape, it is preferable to make the cylinder small or to wind the strands so that the porosity between the strands is large.

(2) The composition of the sizing agent should be determined so that the epoxy ring does not open.

For this purpose, it is desirable to reduce the content of substances that easily react with epoxy rings, such as strong acids and amine compounds.

Next, a method for producing FRP according to claims 4 and 5.6 will be explained.

Examples of the liquid thermosetting resin to be impregnated into the strand include unsaturated polyester resins, epoxy resins, phenol resins, etc., and epoxy resins are particularly preferred.

The above resin may also contain amine compounds, curing agents such as acid anhydrides, curing accelerators such as benzyldimethylamine, fillers such as acid cal, talc, titanium white, pigments, etc. The thermosetting resin of the present invention includes a resin (resin composition) containing such additives, and is collectively referred to as resin in the following description.

The strand is impregnated with an excessive amount of resin according to a conventional method, the excess resin is squeezed to make the resin amount a predetermined amount, and the strand is heated while being passed through a mold having a predetermined shape, or FW
Wrap it around a mold and heat it using the method. The resin of this strand hardens under tension, resulting in high strength and low strength loss after boiling tests or when repeated stress is applied.
You can also get RP.

In addition, the heavy abrasion% (GC) of this strand in FRP is 5
It is appropriate to set it at 0 to 80 wt%, preferably 60 to 75 wt%.

[Function] 20g of glass fiber bundle is mixed with 25ml of dioxane.
The epoxy output amount of the solution extracted under reflux for a period of time is 600 or less, and preferably the solid content of this solution is 0.02
~0.5 gr, more preferably satisfies the above conditions, and has an infrared absorption spectrum near 916 cl' of a solution obtained by ultrasonically cleaning 50 gr of glass fiber bundles with 300 nl of chloroform for 2 hours. Absorbance of epoxy group and aromatic adjacent 2H around 820 cm-'
By using a strand with A/B of 0.2 or more as a reinforcing fiber for FRP, when the absorbance of FRP is A and B, respectively, the bonding force with the matrix resin of the strand FRP is increased, and the strength of FRP is improved.

[Example 1] A sizing agent having the following composition was applied to 23 glass fibers at a solid content of 0.5 wt% and 4,000 fibers were bundled by hand to form a strand.

Composition of sizing agent Emulsified epoxy resin 4.5 wt% (epoxy equivalent 190) γ-aminopropyltriethoxysilane 0.5 wt% higher fatty acid ester 0.6 wt% acetic acid 0.2
wt% This strand is wound into a 16 kg cylinder, and the humidity is 30%.
It was dried in a drying oven with forced circulation of atmosphere.

The drying time was 17 hours, and the drying temperature was 120°C.

This strand was cut into 30+ui and weighed 20g.
The mixture was placed in a flask, 251M of dioxane was added, a reflux condenser was attached, the dioxane was boiled, and extraction was performed for 1 hour.

The solid content in the extract is 0.06g, epoxy L
5t is 330, and put 50g of this 30mm cut strand in a flask and add 300ml of chloroform.
The flask was poured into a water tank equipped with a 40 KHz, 50 W ultrasonic transmitter, and ultrasonic extraction was performed for 2 hours. When the absorbance of aromatic adjacent 2H is B, the ratio of absorbances A and B is 0.
．． It was 25.

This strand was impregnated with a resin composition having the following composition, and a unidirectional reinforced seal 1~ of 70 wt% GC was manufactured by the FW method.

The shear strength of this sheet was 7.56 kg/mITf, and the strength retention rate after boiling for 100 hours was 92%.

Resin composition Epicoat 828 (trade name: oily shell acid) 100 parts by weight Amine curing agent 10 parts by weight [Example 2] Using the same sizing agent as in Example 1, the same procedure was carried out using strands dried at 120°C for 24 hours. We conducted an experiment. The results were as follows.

Epoxy equivalent weight 530 Solid content 0.06 A/B 0-18 Shear strength 7. : 18 kg/mm m' Strength retention rate 90% [Example 3] A similar experiment was conducted using the same sizing agent as in Example 1 and a strand dried at 120° C. for 17 hours. The results were as follows.

Epoxy equivalent: 390 Solid content: 0.016 A/BO, 22 Shear strength: 7.40 kg/mrrr' Strength retention: 90% A similar experiment was conducted using The results were as follows.

Epoxy equivalent weight 840 Solid content 0.05 A/B0.16 Shear strength 7. lokg/m rn' Strength retention rate 87% C Effects of the invention] Glass fiber bundles are used as reinforcing fibers, and the strength is high, and the strength retention rate after one boiling test is high, or the decrease in strength is small when repeated stress is applied. You can roam around FRP.

[Brief explanation of the drawing]

FIG. 4 is a graph showing an infrared absorption spectrum. In the figure, m and n indicate reference lines for determining absorbance.

Claims (6)

[Claims] (1) In a long glass fiber bundle obtained by applying a sizing agent containing epoxy resin to glass fibers, sizing, and drying, the epoxy resin contained in the solution obtained by refluxing and extracting 20g of glass fiber bundles with 25ml of dioxane for 1 hour. A glass fiber bundle having an epoxy equivalent of 600 or less. (2) Solid content in the extract is 0.02-0.5gr
The glass fiber bundle according to claim 1. (3) 50g of glass fiber bundle in 300ml of chloroform
In the infrared absorption spectrum of the solution extracted by ultrasonic cleaning for 2 hours using The glass fiber bundle according to claim 2, wherein A/B is 0.2 or more. (4) A long glass fiber bundle obtained by applying a sizing agent containing an epoxy resin to glass fibers, converging and drying, and epoxy equivalent of a solution obtained by extracting 20g of this glass fiber bundle under reflux for 1 hour using 25ml of dioxane. Impregnating a long glass fiber bundle with a liquid thermosetting resin of 600 or less,
A method for producing a fiber-reinforced resin body, which comprises curing the glass fiber bundle under tension. (5) Solid content in the extract is 0.02-0.5gr
The manufacturing method according to claim 4. (6) 50g of glass fiber bundle in 300ml of chloroform
In the infrared absorption spectrum of the solution extracted by ultrasonic cleaning for 2 hours using 6. The manufacturing method according to claim 5, wherein A/B is 0.2 or more.