JPH0270352A - Phenol resin for mold - Google Patents

Abstract

PURPOSE:To obtain phenol resin for mold having high strength and rapid hardenability at the time of molding by specifying mixed-melting of random novolak type and high ortho type. CONSTITUTION:The novolak type phenol resin used as molding binder is obtd. by reacting phenol kind and aldehyde kind under acidic catalyst. Then, the random novolak type phenol resin A is made to 0.95 - 1.16 combined form ortho/para ratio obtd. by using the strong acid as the catalyst. Further, the high ortho type phenol resin B is made to 1.5 - 5.0 combined form ortho/para ratio obtd. by using organic metal salt as the catalyst. These are mixed and melted at 95/5 - 50/50 A/B wt. ratio to obtain the phenol resin for mold. This phenol resin for mold has high strength and rapid hardenability at the time of molding.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a phenolic resin used as a mold binder, and more particularly to a novolak type phenolic resin that has exceptional molding strength and fast curing properties.

<Prior Art> Conventionally, a novolak type phenolic resin obtained by reacting phenols and aldehydes under an acidic catalyst has been used as a phenolic resin for molds.

Novolac-type phenolic resins include random novolacs with a low ortho/para bonding mode obtained using a strong acid as a catalyst, and high ortho novolacs with a high bonding mode ortho/para ratio obtained using an organic acid metal salt as a catalyst. Both are used as binders for molds.

However, although the former has high strength during molding, it has the disadvantage of slow curing speed.

The latter has a fast curing speed during molding, but has the disadvantage of poor strength.

Therefore, it has been desired to develop a novolac type phenolic resin that has a fast curing speed and high strength during molding.

<Problems to be Solved by the Invention> The present invention has been made in order to eliminate the above-mentioned drawbacks, and aims to provide a phenolic resin for molds that has high strength and fast curing properties during molding.

<Means for Solving the Problems> In order to solve the above problems, the present inventors conducted intensive studies and discovered a novolac-type phenolic resin that has both quick curing properties and high strength during molding, and has developed the present invention. Ta.

That is, the present invention provides a novolac type phenol resin obtained by reacting phenols and aldehydes under an acidic catalyst, in which (A) a bond mode ortho/para ratio obtained using a strong acid as a catalyst is 0.95 to 1.16; Random novolak type phenolic resin.

and (B) a high ortho type phenol resin with a binding mode ortho/para ratio of 1.5 to 5.0, obtained using an organic acid metal salt as a catalyst, is mixed at an A/8 ratio (weight j 1 part ratio) of 9515 to 50150. In phenolic resins for molds, which are obtained by melting and have high strength and fast curing properties during molding, and in novolac type phenolic resins, which are obtained by reacting phenols and aldehydes under an acidic catalyst, (A) using a strong acid as a catalyst; A random novolak type phenolic resin having a binding mode ortho/para ratio of 0.95 to 1.16.

and (B) a high ortho type phenol resin with a binding mode ortho/para ratio of 1.5 to 5.0 obtained using an organic acid metal salt as a catalyst is mixed and melted at an A/B ratio (parts by weight) of 9515 to 50150. 0.5 to 2 parts by weight of a silane coupling agent is added to 100 parts by weight of the resulting resin, and the mixture is mixed and melted to produce a phenolic resin for molds that has high strength and fast curing properties during molding.

The ortho/para ratio used in the present invention was determined using an IR (infrared absorption spectrum) measurement method using the KBr tablet method.
It was calculated from the absorbance ratio of the para bond indicated by c7 and the ortho bond indicated by 760 cm'.

The phenols used in the present invention include phenol, orthocresol, metacresol, paracresol, bisphenol A, and the like.

Examples of aldehydes include aldehydes such as formaldehyde and acetaldehyde, aldehydes such as trioxane, paraform, and hexamine, and aqueous solutions thereof.

Catalysts include acids such as sulfuric acid, hydrochloric acid, oxalic acid, para-toluenesulfonic acid, and phosphoric acid, and organic metal salts such as zinc acetate and magnesium acetate.

Zinc borate, zinc naphthenate, zinc lactate, etc. are used.

As a silane coupling agent, aminomethoxysilane,
Aminoethoxysilane or the like is used.

The phenolic resin for spinning molds that has high strength and fast curing properties during molding of the present invention has a blend composition ratio (parts by weight) of (A) random novolak and (B) high alternating hollak of 9515.
~50,150.

When the composition of the random novolak is increased from the above conditions, high molding strength is exhibited, but the curing speed becomes slow.

Furthermore, when the composition of the high-ortho novolak is increased from the above conditions, the molding hardenability is exhibited, but the strength is reduced.

Furthermore, the phenolic resin for castings which has high strength and quick hardening properties during molding of the present invention is random novolak (A) and (B).
Resin 1 obtained by uniformly blending the high-ortho novolak composition ratio (parts by weight) of 9515 to 50150
0.00 parts by weight and 0.5 to 2 parts by weight of a silane coupling agent are added and melted.

By adding a silane coupling agent, the strength of the resin can be further increased without impairing fast curing properties.

<Example> The present invention will be explained in more detail with reference to Examples.

The invention is not limited to the examples.

Note that "mouth r part" or "1%" is based on weight unless otherwise specified.

Synthesis Example 1 1000 parts of phenol, 511 parts of 50% formalin, and 10 parts of Shu* were placed in a separable three-way flask equipped with a thermometer, condenser, and stirrer, and the temperature was gradually raised to reflux, followed by reflux reaction for 2 hours. The flask was then dehydrated under reduced pressure and taken out when the temperature inside the flask reached 160°C to obtain 800 parts of a solid resin at room temperature.

The bonding mode ortho/para ratio calculated from IR (infrared absorption spectrum) of the resin thus obtained was 0.95.
Met.

Synthesis Example 2 1,000 parts of phenol, 382 parts of 50% formalin, and 5 parts of zinc acetate were charged into an apparatus similar to Synthesis Example 1, and the mixture was gradually heated to reflux, followed by a dehydration reflux reaction for 3 hours.

Next, dehydration was performed under reduced pressure until the resin temperature in the flask reached 16
It begins to settle when it reaches 0℃, and the resin 800 is solid at room temperature.
I got the department. The binding mode ortho/para ratio of the thus obtained resin calculated by IH was 3.0. .

Example 1 Resin 800 obtained in Synthesis Example 1 was placed in the same apparatus as Synthesis Example 1.
1 part, 200 parts of the resin obtained in Synthesis Example 2 were charged and heated.
The mixture was mixed and melted at 50° C. for 2 hours, and then taken out to obtain a solid resin at room temperature.

Example 2 A solid resin at room temperature was obtained from 600 parts of the resin of Synthesis Example 1 and 400 parts of the resin of Synthesis Example 2 in the same manner as in Example 1.

Example 3 Resin 80 obtained from Synthesis Example 1 was placed in the same apparatus as Example 1.
0 parts, 200 parts of the resin obtained in Synthesis Example 2, aminomethoxysilane (trade name KBR-60, manufactured by Shin-Etsu Chemical Co., Ltd.)
2) 15 parts were charged and heated, mixed and melted at 150° C. for 2 hours, and then taken out to obtain a resin that was solid at room temperature.

Example 4 In the same manner as in Example 3, from 600 parts of the resin of Synthesis Example 1, 400 parts of the resin of Synthesis Example 2, and 10 parts of aminoethoxysilane (K B-903, manufactured by Shin-Etsu Chemical Co., Ltd.), a solid at room temperature was prepared. Resin was obtained.

Example 5 Synthesis Example 1 as a random novolac type phenol resin
The resin was used as is. .

Example 6 The resin of Synthesis Example 2 was used as is as a high ortho-type phenol resin.

Test method Resin coated sand was produced using Grammar for each of the resins obtained in Examples 1 to 4 and Examples 5 to 6, and their performance was compared and studied. Temperature 130℃
8,000 parts of Sanei No. 6 silica sand and 160 parts of resin heated to Make it into granules; 5
Then, 8 parts of calcium stearate was added, mixed for 60 seconds, and taken out to obtain resin coated sand.

The properties of each resin obtained and the cost characteristics of the resin coated sand are shown below.

Table 1 (Example) Example 1 Softening point ('C) 85 Gel time 150 150℃ seconds 10% honey added Flow-Hexamine 10X addition 60 Bending strength kg/cJ 45 Fusion point ('C) 100 hot tensile strength 1/- at 250℃ 40 seconds 100 60 seconds 12.1 80 seconds 14.5 Vent (250℃7 100 seconds) (m) 1, 1 9.4 13.2 1.1 100 100° ++, 0 10.3 13.3 12.8 +6.0 14.5 1.1 1.1 Table 2 (Example) Example 5 Softening point ('C) 85 Gel time/70 150℃ seconds hexamine 10% addition Flowing Garden Hexamine 70 10% addition) Bending strength (kg/aJ) 48 Fusion point ('C) 100 hot tensile strength (250℃) (kg/ad) 40 seconds 7゜ 60 seconds 9° 80 seconds 13° Bend (250℃/　1゜ 100 seconds) (-) 15° 15° 14.

O2 <Effects of the Invention> It was confirmed that the phenolic resin for molds according to the present invention has high strength during molding and fast curing. Resins with these properties have excellent workability during molding and can be widely used as binders for molds in the shell molding method.

Patent applicant Gunmo Chemical Industry Co., Ltd.

Claims (1)

[Scope of Claims] 1) A novolac type phenol resin obtained by reacting phenols and aldehydes under an acidic catalyst, wherein (A) the ortho/para ratio of the bonding mode obtained using a strong acid as a catalyst is 0.95 to A/B ratio: a random novolac type phenolic resin having an A/B ratio of 1.16; A phenolic resin for molds that has high strength and fast curing properties when molded, obtained by blending (parts by weight) in a ratio of 95/5 to 50/50. 2) In the novolac type phenolic resin obtained by reacting phenols and aldehydes under an acidic catalyst, (A) a random bonding mode ortho/para ratio obtained by using a strong acid as a catalyst and having an ortho/para ratio of 0.95 to 1.16. A novolac type phenolic resin and (B) a high ortho type phenol resin with a binding mode ortho/para ratio of 1.5 to 5.0 obtained using an organic acid metal salt as a catalyst, with an A/B ratio (parts by weight ratio). 0.5 to 2 parts by weight of a silane coupling agent is added to 100 parts by weight of the resin obtained by blending 95/5 to 50/50, resulting in high strength and fast curing when molded by blending. Phenolic resin for molds.