An environmentally friendly polyol self-hardening resin binder

Abstract

The present invention relates to the technical field of the foundry industry, and in particular to an environmentally friendly no-bake polyol resin binder. To address this problem, the following solution is proposed, comprising a polyol resin component (I) and a polyisocyanate, characterized in that the polyol resin component (I) is prepared by mixing an amino polyol, a polyether polyol, and an aromatic hydrocarbon solvent. By using polyether polyols, polyester polyols, or amino polyols instead of phenylene ether-type phenolic resins as the polyol resin component (I), the resin contains no free phenol or free formaldehyde, thereby reducing health hazards to foundry workers, lowering VOC levels, and achieving environmental friendliness.

Description

Technical Field

[0001] The invention relates to the technical field of foundry industry, in particular to an environmentally friendly polyol self-hardening resin binder. Background Art

[0002] In the foundry industry, self-hardening resin sand molding and core making processes have been accepted by most small and medium-sized core sand manufacturers worldwide. Due to its compact and hard molding sand, easy control, and high casting dimensional accuracy, self-hardening resin sand technology is now widely used for casting various types of metal castings. Currently, the casting resins used in self-hardening resin sand technology are generally divided into the following three categories:

[0003] (1) Furan resin:

[0004] Furan resins are a general term for a series of new compounds obtained by modifying urea-formaldehyde resins, phenol-formaldehyde resins, or urea-phenol-formaldehyde resins with furfuryl alcohol. Furan resins contain a furan ring, highly reactive hydroxyl and methylol groups, and hydrogen bonds, resulting in a relatively low molecular weight. Under acid catalysis, the chain-like compounds undergo dehydration, the furan ring double bonds break, and then cross-link to form three-dimensional macromolecular organic compounds.

[0005] (2) Alkaline phenolic resin:

[0006] Ester-hardened alkaline phenolic resin is an aqueous solution of alkaline resol phenolic resin formed by the condensation of phenol and formaldehyde under a strong alkaline catalyst. The curing agent is an organic ester, which does not contain nitrogen, phosphorus, or sulfur and produces minimal gassing. The organic ester curing agent directly participates in the resin's hardening reaction. At room temperature, most alkaline phenolic resins undergo a cross-linking reaction. Under the heat of pouring, the uncross-linked resin continues to undergo a polycondensation reaction, initially exhibiting plasticity before transforming into a rigid, high-strength material known as "secondary hardening." This characteristic alleviates stress in the core caused by thermal expansion of sand, making it particularly suitable for preventing thermal cracking defects in thin-walled steel castings.

[0007] (3) Polyurethane resin:

[0008] Polyurethane resin is composed of a hydroxyl-containing polyol resin (component I) and polyisocyanate (component II) as a binder and a liquid tertiary amine as a catalyst.

[0009] Production practice shows that furan resins, due to the presence of nitrogen, sulfur, and phosphorus in their acid curing agents, are prone to pores (nitrogen pores) and thermal cracking during casting. In recent years, they have been gradually replaced by alkaline phenolic resins. However, the alkaline phenolic resin process requires a relatively high dosage, resulting in low tensile strength and a short shelf life. The hardening reaction mechanism of polyurethane resins is that the two double bonds (RN=C=O) of the isocyanate group in the polyisocyanate molecule are chemically reactive and easily attacked by the hydroxyl groups on the polyol resin, causing hydrogen atoms to transfer to nitrogen atoms and then linking hydrogen and oxygen atoms with carbon atoms, leading to hardening. This cross-linking reaction does not produce small molecular byproducts. However, conventional phenyl ether phenolic resin polyols, used as component I, emit harmful gases during the casting process, causing significant pollution.

[0010] The above-mentioned problems need to be solved urgently, so it is necessary to design an environmentally friendly polyol self-hardening resin binder to solve the above problems. Summary of the Invention

[0011] The purpose of the present invention is to solve the problems in the prior art and to propose an environmentally friendly polyol self-hardening resin binder.

[0012] In order to achieve the above object, the present invention adopts the following technical solutions:

[0013] The present invention provides an environmentally friendly polyol self-hardening resin binder, comprising a polyol resin component I and polyisocyanate, wherein the polyol resin component I is prepared by mixing amino polyol, polyether polyol and aromatic hydrocarbon solvent.

[0014] Preferably, the specific preparation ratio and method of the polyol resin component I are divided into the following steps:

[0015] S1: 10-40% amino polyol, 30-60% polyether polyol and 50-60% aromatic hydrocarbon solvent are mixed in a container. The aromatic hydrocarbon solvent can be any one of S-100, S-150 and S-200 or a mixture thereof.

[0016] S2: After the mixing is completed, heating and stirring are performed inside the container for 1 hour, and after the stirring is completed, a polyol resin component I is obtained;

[0017] S3: Mix 50-80% polyisocyanate and 20-50% aromatic solvent in a container. The aromatic solvent can be any one of S-100, S-150, and S-200 or a mixture thereof.

[0018] S4: Stir at room temperature for 1 hour until the mixture is evenly mixed to obtain the curing agent.

[0019] Preferably, the prepared curing agent is mixed with the polyol resin component I to prepare a polyol self-hardening resin binder.

[0020] Compared with the prior art, the present invention provides an environmentally friendly polyol self-hardening resin binder with the following beneficial effects:

[0021] 1. This environmentally friendly polyol self-hardening resin binder uses polyether polyol, polyester polyol, and amino polyol instead of phenyl ether phenolic resin as the polyol resin component I. The resin does not contain free phenol and free formaldehyde, thereby reducing health hazards to foundry workers, reducing VOC, and being environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the production process of an environmentally friendly polyol self-hardening resin binder proposed by the present invention; DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0024] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", etc., indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as limiting the present invention.

[0025] Reference Figure 1 , an environmentally friendly polyol self-hardening resin binder, comprising a polyol resin component I and polyisocyanate, characterized in that the polyol resin component I is made by mixing amino polyol, polyether polyol and aromatic hydrocarbon solvent.

[0026] In a specific embodiment, the specific preparation ratio and method of the polyol resin component I are divided into the following steps:

[0027] S1: 10-40% amino polyol, 30-60% polyether polyol and 50-60% aromatic hydrocarbon solvent are mixed in a container. The aromatic hydrocarbon solvent can be any one of S-100, S-150 and S-200 or a mixture thereof.

[0028] S2: After the mixing is completed, heating and stirring are performed inside the container for 1 hour, and after the stirring is completed, a polyol resin component I is obtained;

[0029] S3: Mix 50-80% polyisocyanate and 20-50% aromatic solvent in a container. The aromatic solvent can be any one of S-100, S-150, and S-200 or a mixture thereof.

[0030] S4: Stirring at room temperature for 1 hour to obtain a curing agent after mixing evenly.

[0031] In the above technical solution, the comparative physical indicators of the polyol resin component I and the traditional phenyl ether type phenolic resin polyol component I are specifically shown in the figure below:

[0032]

[0033] In a specific embodiment, the prepared curing agent is mixed with the polyol resin component I to prepare a polyol self-hardening resin binder.

[0034] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. An environmentally friendly polyol self-hardening resin binder, comprising a polyol resin component I and polyisocyanate, characterized in that: The polyol resin component I is prepared by mixing amino polyol, polyether polyol and aromatic hydrocarbon solvent. The specific production ratio and method of the polyol self-hardening resin binder are divided into the following steps: S1: 10-40% amino polyol, 30-60% polyether polyol and 50-60% aromatic hydrocarbon solvent are mixed in a container. The aromatic hydrocarbon solvent is any one of S-100, S-150 and S-200 or a mixture thereof. S2: After the mixing is completed, heating and stirring are performed inside the container for 1 hour, and after the stirring is completed, a polyol resin component I is obtained; S3: Mix 50-80% polyisocyanate and 20-50% aromatic solvent in a container. The aromatic solvent can be any one of S-100, S-150, and S-200 or a mixture thereof. S4: stirring at room temperature for 1 hour to obtain a curing agent after uniform mixing; The prepared curing agent is mixed with the polyol resin component I to prepare a polyol self-hardening resin binder.

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