BRPI0903539A2 - use of phyllosilicates as a component for polyurethane manufacture - Google Patents

Abstract

USE OF PHILOSILICATES AS A COMPONENT FOR THE MANUFACTURE OF POLYURETHANE. Flexible polyurethane foams were prepared using phyllosilicates. The use of this material promoted an increase in the value of CFD ~ 40 ~, a reduction in the hysteresis values, as well as a reduction in the burning power of the material. The preparation process uses phyllosilicates, used in obtaining the polymeric matrix, polyol, TDI, index of controlled isocyanate and water and dichloromethane as the blowing agent. By the same principle used in flexible foams, other polyurethanes can be manufactured using phyllosilicates.

Description

UTILIZATION OF PHILOSILICATES AS A COMPONENT FOR DPOLIURETAN MANUFACTURE.

The present invention is characterized by the use of component components phyllosilicates in the manufacture of polyurethanes, whether or not replacing part of the polyol used.

Silicates are abundant in the earth's crust, and 25% of the minerals belong to this class. Silicates are formed by structural units containing tetrahedra represented by SiO4. Within the class of silicates is inserted the phylosilicate subclasses.

Polyurethane is a polymer formed by linear macromolecules that present in the chain the repetition of the urethane functional group (Figure 1).

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Figure 1: Generic Polyurethane Structure

Its formulation was patented by chemist Otto Bayer in 1937, and is considered one of the most successful polymeric materials of this century due to its softness.

In the area of flexible products, polyurethane has been mainly popularized in our automotive mattress, upholstery and seat segments.

In the area of rigid products, polyurethane is widely used and may be present:

- in the automotive industry (in panels, bumpers, doors and others)

- In civil construction (in thermal insulation, crown molding, ceilings and others)

- In boat building

- As thermal insulation in refrigerators

- In addition to other usesSome products are used in the synthesis of polyurethanes in order to modify the final properties of this material, such as fillers and copolymers.

A widely used filler in flexible polyurethane foams is calcium carbonate due to the following factors: cost, non-abrasiveness, non-toxicity and light color which facilitates pigmentation.

However, this material, used in large quantities, favors a reduction in the quality of flexible foams.

Another material commonly used in the synthesis of polyurethanes is oscopolymers. These are foreign materials to the polymer chain that become part of the chain because they participate in polymerization reactions.

In flexible polyurethane foams it is very common to use copolymers, either to increase hardness, flexibility, tear resistance or foam resilience.

From the above considerations, the present invention is characterized by providing a method of preparing flexible polyurethane foams with homogeneous structure and employing percentage phyllosilicates ranging from 1 to 70% within the polymer matrix. The polyol used in the foam formulation may be replaced in part by the phyllosilicate, which acts as a copolymer in the foam.

For a good understanding of the invention non-limiting examples will be cited, presenting a formulation where 15% of the polyol was replaced by steatite (phyllosilicate) and a pure foam formulation.

Example 1: Synthesis of flexible polyurethane foams.

To perform the present work, flexible polyurethane foams were synthesized, according to the formulation and methodology described below.

For the manufacture of flexible foams, the formulations described in table 1 were used. Table 1: Examples of foam formulations with and without phyllosilicates.

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For the example described above, steatite was used, but other phyllosilicates may be used.

As the phyllosilicate entered the formulation replacing part of the polyol, it participates in chemical synthesis reactions of polyurethane foams. Thus other polyurethanes, in addition to foams, may also have the polyol substituted by phyllosilicates.

Industrial scale tests were performed using an expansion box with 2.25 χ 1.95 χ 1.30 m, where steatite and serpentinite tests were performed. Both showed the same behavior, replacing part of the polyol in the foam formulation, showing that other phyllosilicates can be used because they have a similar chemical structure.

The thermal analysis of the serpentinite shows that it loses water, either from moisture, or present in its structure. As heat is absorbed to release this water, this reduces the burning power of materials with this present phyllosilicate.

This behavior was observed in serpentinite polyurethane foam burning tests. Due to their similar structure, other phyllosilicates exhibit the same flame retardant behavior.

In a disposable plastic container, polyol and phyllosilicate were placed, when used, and the mixture was stirred until complete homogenization. Then, the amine, the surfactant and water were added. The mixture was mechanically stirred for 30 sec. Immediately afterwards the catalyst (tin octoate) was added and the mixture stirred again for 30 seconds. The isocyanate was introduced and subjected to 4 seconds stirring. After this stirring, the mixture was poured into a wooden box with 32 x 36 cm of base by 23 cm of height. After expansion, the foams were removed from the box and left to stand for 72 h to cure, and then the mechanical properties were analyzed, which will be described below.

Mechanical Analysis of Foams

In the mechanical analyzes, the flexible foams were submitted to four decompression-decompression cycles, with 70% deformation, aiming to evaluate the hysteresis behavior and 40% deformation (CFD40). The conditions of the experiment were determined by ISO 3386.

In flexible foams, hysteresis is related to system energy loss when it is subjected to a compression-decompression cycle.

The values found for the mechanical properties of the synthesized foams were as follows:

Table 1: Foam Properties

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Table 1 shows that the steatite foam presented higher CFD40 values than the pure foam. This fact was already expected since steatite behaves as a copolymer in the polymeric matrix. It can also be observed that the foamed foam presented lower hysteresis values than the pure one.

Claims (7)

USE OF PHILOSILLECATES AS A COMPONENT FOR POLYLURETAN MANUFACTURE 1. - Process for the preparation of flexible, semi-rigid polyurethane foams with one or more phyllosilicates. 2. - Preparation process of flexible, semi-rigid polyurethane foams with one or more phylosilicates modified by treatment with acids, bases, copolymers or others. 3. - Polyurethane foam preparation process according to items 1 and 2, using polyol, diisocyanate (TDI or MDI (modified or not) or other isocyanate), surfactant, blowing agents (water, chloride or other) and catalysts ( amines, tin octanoate or other). 4. Process for preparing polyurethane foams according to items 1, 2 and 3 with one or more phyllosilicates with concentrations of 1 to 70%. 5. - Process of preparation of polyurethane foams, according to items 1 to 4, for use: a) In the furniture industry (mattresses, upholstery, chairs, etc.) b) As thermal insulation (in construction, manufacture of thermal boxes, chilled boxes , etc.) c) In the automotive industry (in seats, headrests, panels, bumpers, etc.) d) In the shoe industry. 6. Preparation process of other polyurethanes, in addition to foams, where the polyol is replaced by a phyllosilicate, and the same conditions as described in items 1 to 5 apply. 7.- Polyurethanes preparation process, according to items 1 to 6, using phyllosilicate as flame retardant.