CN115819705A - Full-water low-density packaging foam - Google Patents

Abstract

The invention relates to an all-water low-density packing foam, which belongs to the technical field of packing foam. Including component A and component B, the mass ratio of the two is 1:(1.0‑1.5). Among them, component A is composed of silica sol, catalyst and surfactant, wherein silica sol accounts for 90-95% of the total mass of component A, catalyst accounts for 4-7% of the total mass of component A, and surfactant accounts for Component A 2‑4% of the total mass. B component is isocyanate. In the present invention, the reaction product of isocyanate and water and silicon dioxide in silica sol are used as a material matrix, water in silica sol is used as a chemical foaming agent, and nanoscale silicon dioxide particles in silica sol are used as a heterogeneous nucleating agent , In the case of ensuring environmental protection performance, the cost of materials is greatly reduced.

Description

A kind of all-water low-density packaging foam

technical field

The invention relates to an all-water low-density packaging foam, which is especially suitable for the field of shock-absorbing packaging of fragile items such as precision instruments, valuables, and porcelain, and belongs to the technical field of packaging foam.

Background technique

Polyurethane materials are widely used in life and production. Compared with other materials, polyurethane is a relatively expensive material, but it is still widely used due to its excellent performance. Low-cost polyphenylene foam is used more in packaging foam, and polyurethane packaging foam is mostly used in some high-end products, which can realize 360-degree wrapping of the object to be protected without dead ends. Traditional polyurethane packaging foams are mostly polyether foams, that is, polyether polyols and isocyanates are used as the material matrix, and water or other low-boiling substances are used as foaming agents. Since polyether polyols and isocyanates are derived from petrochemicals, the price is relatively high; However, the density of preformed polyphenylene foam is above 20kg/m ³ , the packaging weight is heavy, and it is inconvenient to load, unload and transport.

Silica sol is a colloidal solution, odorless, non-toxic, and its molecular formula can be expressed as mSiO ₂ nH ₂ O. Due to the small particle size (10 - 20nm) of silica sol colloidal particles and relatively large specific surface area, the particles themselves are colorless and transparent, and do not affect the true color of the covered object. Silica sol has a low viscosity and can penetrate wherever water can penetrate, so it has very good dispersibility and permeability when mixed with other substances. When the moisture of silica sol evaporates, the colloidal particles are firmly attached to the surface of the object, and the silicon-oxygen bond is formed between the particles, which is a good adhesive.

At present, the main production methods of silica sol are: silicon dissolution method and ion exchange method. The silica sol of the present application is also made by following two processes.

1. Silicon dissolution method: The method of preparing silica sol by using inorganic or organic bases as catalysts and reacting elemental silicon with pure water is called silicon dissolution method. The advantage of this method is that there is less impurity content in the finished silica sol, the colloidal particle shape, particle size, viscosity, ph value, density, and purity of silica are easy to control, the colloidal particle shape is round and uniform, the structure is compact, and the silica sol Good stability.

2. Ion exchange method: The ion exchange method is currently the most researched and most mature process, usually divided into the following two steps ① preparation of active silicic acid ② growth and concentration of colloidal particles; this method should be noted that there is generally a small amount of silicic acid in the finished product Impurities exist and need to be purified. An effective way to remove impurities is centrifugation.

The main raw material of traditional polyurethane packaging foam is polyether polyol, and the main raw material of synthetic polyether polyol is initiator and propylene oxide. Commonly used starters include glycerin, sucrose, sorbitol, etc., and propylene oxide comes from petrochemical industry. Petroleum is a non-renewable resource, and its price fluctuates greatly, and the cost is getting higher and higher. Besides, my country is a country with little oil. Mainly rely on imports.

The use of silica sol foam instead of traditional polyurethane packaging foam helps to reduce my country's dependence on imported oil and reduce the cost of the packaging industry to a certain extent, but there is no public report in the prior art.

Contents of the invention

The invention provides an all-water low-density packaging foam, which uses the reaction product of isocyanate and water and silicon dioxide in silica sol as a material matrix, uses water in silica sol as a chemical foaming agent, and uses nano-scale foam in silica sol As a heterogeneous nucleating agent, silica particles greatly reduce material costs while ensuring environmental performance.

A kind of low-cost packing foam, its special feature is to comprise by A component and B component, the mass ratio of the two is 1:(1.0-1.5);

The A component is composed of silica sol, catalyst and surfactant, wherein the silica sol accounts for 90-95% of the total mass of A component, the catalyst accounts for 4-7% of the total mass of A component, and the surfactant accounts for A group 2-4% of the total mass.

The B component is isocyanate.

Preferably, the silica sol is an alkaline silica sol, wherein the concentration of silicon dioxide is 30-40%;

Preferably, the catalyst is a reactive catalyst;

Preferably, the catalyst is one or more mixtures of EF-100 catalyst produced by Mitu High-tech Materials Group, NE310 produced by Evonik Specialty Chemicals (Shanghai) Co., Ltd., and DABCO-T;

Preferably, the surfactant is B8863Z surfactant produced by Evonik Specialty Chemicals (Shanghai) Co., Ltd.;

The isocyanate is any one of PM-200 produced by Wanhua Chemical, 5005 produced by Huntsman, and M200 produced by Mitsui.

A kind of all-water low-density packing foam of the present invention is the packing foam that adopts silica sol and isocyanate to produce, there is no added type physical flame retardant and other plasticizers in the system of the present invention, thereby obtained relatively low odor test value and formaldehyde emissions and benzene content. The system of the present invention does not need to use conventional polyether polyols or polyester polyols, so that the cost of component A can be greatly reduced. The silica sol used in the present invention is alkaline silica sol, and concentration is 30-40%, and the nanoscale silicon dioxide in silica sol acts on the cell of foam together with surfactant as heterogeneous nucleating agent, after reaction finishes Nano-scale silica particles are dispersed in the foam matrix to provide support for the physical properties of the foam, and the water in the silica sol acts as a chemical blowing agent and reacts with PM-200 to generate carbon dioxide.

In the present invention, the water in the silica sol is used as a chemical foaming agent, and under the action of a catalyst, the isocyanate reacts with water to generate carbon dioxide, and the nano-scale silicon dioxide in the silica sol acts as a heterogeneous nucleating agent and acts together with a surfactant Due to the formation of cells, the generated carbon dioxide exists in the system in the form of tiny bubbles. Due to the existence of surfactants, the bubble bubble phenomenon is reduced. As the reaction progresses, the viscosity of the system increases, and finally in each Under the combined action of various factors, the cells will open, and the cells will become an open-cell honeycomb-like structure. After the reaction is completed, silica will be dispersed in the foam matrix (cell wall) to provide support for the physical properties of the foam; use high-pressure airless spraying The density after spraying from the equipment is 9-11kg/m ³ , the odor level (80°C) is 3, the formaldehyde emission is ≤10mg/kg, and the benzene series (benzene, toluene, xylene, styrene) are lower than the detection limit.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

Example 1

An all-water system low-density packaging foam in this example is formed by polymerizing component A and component B. The foam produced by component A and component B is in a weight ratio of 1:1.1. The specific ingredients and dosage are as follows:

Example 2

The specific composition and consumption of the A and B components of the present embodiment are as follows:

The density, odor, formaldehyde emission and benzene series content four performance indicators achieved by the above-mentioned embodiments 1 and 2 and the existing traditional polyurethane packaging foam are as follows:

The performance index of above-mentioned embodiment 1,2 obtains according to following test standard:

Odor level test standard: VDA270:1992,

Benzene substances test standard: VDA277:1995,

Formaldehyde emission test standard: VDA275:1994.

Use the above components A and B to mix and stir according to the mass ratio of 1:1.1 to make foam products.

Embodiment 1 and 2, change catalyst consumption, catalyst increases consumption to 7 parts from 4 parts, tensio-active agent is constant, colloidal silica reduces to 91 parts from 94 parts, and foam density increases to 10.6 from 9.4, and other environmental performances are substantially unchanged. Change. The unit price of component A in Examples 1 and 2 is 9,000-10,000 yuan/ton, and the unit price of component A of traditional polyether packaging foam is about 15,000 yuan/ton, and the cost is significantly reduced.

After the A component of the above-described embodiment uses silica sol, the foam performance is basically the same as that of the traditional polyurethane packaging foam, and the density is close to that of the traditional polyurethane packaging foam, which is smaller than the polystyrene foam, so that the foam with very little weight can be used to protect the articles to be packaged. It has a good protective effect and is more convenient for loading, unloading and handling; the environmental protection performance is better than that of traditional polyurethane packaging foam, while the cost is greatly reduced, and the harm to the practitioners and users is also reduced. In terms of environmental protection performance, the foam made of silica sol is better than the traditional polyurethane packaging foam. Since polyether is not used, the impurities in polyether such as benzene, formaldehyde and other volatile organic compounds are greatly reduced.

Claims (6)

1. The full-water low-density packaging foam is characterized by comprising a component A and a component B, wherein the mass ratio of the component A to the component B is 1 (1.0-1.5)

The component A consists of silica sol, a catalyst and a surfactant, wherein the silica sol accounts for 90-95% of the total mass of the component A, the catalyst accounts for 4-7% of the total mass of the component A, and the surfactant accounts for 2-4% of the total mass of the component A:

the component B is isocyanate.

2. An all-water low density packaging foam according to claim 1, wherein said silica sol is an alkaline silica sol having a silica concentration of 30-40%.

3. An all-water low density packaging foam according to claim 1 wherein said catalyst is a reactive catalyst.

4. An all-water low density packaging foam according to claim 1 or 3 wherein the catalyst is one or more of EF-100 brand catalyst from maitake high new materials group, NE310, DABCO-T from shanghai specialty chemicals (shanghai) ltd.

5. An all-water low density packaging foam according to claim 1 wherein said surfactant is a surfactant having a designation of B8863Z manufactured by shanghai specialty chemicals (shanghai) ltd.

6. An all-water low-density packaging foam according to claim 1, wherein said isocyanate is any one of PM-200 produced by Wawawa chemical, 5005 produced by Hensman, and M200 produced by Mitsui Japan.