Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – From carboxylic acid or derivative thereof
Reexamination Certificate
2002-01-09
2003-12-16
Acquah, Samuel A. (Department: 1711)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
From carboxylic acid or derivative thereof
C528S275000, C528S283000, C528S300000, C528S302000, C528S308000, C528S308600
Reexamination Certificate
active
06664363
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to low viscosity aromatic polyester polyols having an average functionality of about two and methods for preparing such polyols. In particular, the invention relates to low viscosity aromatic polyester polyols having an average functionality of about two formed by inter-esterification of a phthalic acid based material with diethylene glycol, a higher functional polyol having an average functionality of greater than two, and a long chain alkyl acid, ester or oil. The resulting aromatic polyester polyol has an average functionality of about two and has a lower dynamic viscosity as compared to the esterification product of a phthalic acid based material with diethylene glycol alone.
2. Description of the Related Art
Polyols are useful reactants in preparing a variety of polymeric or resin compositions. Aromatic polyester polyols are widely used in the manufacture of polyurethane and polyurethane-polyisocyanurate foams and resins. Typically, polyols are employed in reactions involving curing or crosslinking with polyisocyanate materials having at least two isocyanate groups per mole, reactions involving melamines or formaldehyde resins, and esterification reactions with unsaturated monobasic fatty acids to form alkyl resins.
Aromatic polyester polyols are attractive because they tend to be low in cost, yet can be used to produce a wide variety of cellular foams having excellent properties and adaptable for many end use applications. One class of aromatic polyester polyols that has enjoyed wide commercial success comprises the polyol products produced by esterification of phthalic acid or phthalic acid anhydride with an aliphatic polyhydric alcohol. For example, a diethylene glycol phthalate is available commercially from Stepan Company, Northfield, Ill. Such a polyol is a somewhat viscous liquid product, with a desirably high aromatic ring content, and a desirably low acid number. This type of polyester polyol is capable of reacting with organic isocyanates to produce, for example, coatings, adhesives, sealants, and elastomers (“CASE materials”), that can have excellent characteristics, such as tensile strength, adhesion, and abrasion resistance.
One problem generally encountered when using aromatic polyester polyols is that they are characteristically high in dynamic viscosity, making handling very difficult. Often, aromatic polyester polyols must be diluted or dissolved in relatively large amounts of a suitable solvent to enable producing low viscosity, easy-to-apply coating compositions upon being mixed with a curing or crosslinking agent.
Ideally, an aromatic polyester polyol has a dynamic viscosity that is sufficiently low to allow ease of pumping and mixing without the use of solvents or other viscosity modifying additives. An aromatic polyester polyol having too great a dynamic viscosity can cause difficulties in transfer of the material, as for example from storage to reactor or from the final product to the final application of the product. Excessive dynamic viscosity also can be a serious obstacle to efficient mixing with other CASE material ingredients, such as an isocyanate. Several solutions to this viscosity problem have been offered. See, for example, U.S. Pat. No. 4,644,027 (to Stepan Company) and U.S. Pat. No. 4,812,533 (to CasChem, Inc.), and Romanian Pat. App. 83,203. See also, for example, Liu, D. et al., Tuliao Gengye, 1988, 5, 1-3:
High Solid alkylated Resin Baked Paint
(Shenyang Inst. Chem. Co.). However, these prior art solutions are often complicated, expensive, difficult to readily implement, and may produce a polyol having a functionality of less than 2.
Thus, there is a need for low viscosity aromatic polyester polyols having an average functionality of about two that are economical to produce and can be converted into cellular foams and other CASE materials having excellent properties.
SUMMARY OF THE INVENTION
The present invention relates to a new and surprisingly useful class of low viscosity aromatic polyester polyols having an average functionality of about two, comprising the inter-esterification reaction product of at least one phthalic acid based material, at least one aliphatic diol, at least one higher functional polyol compound, and at least one hydrophobic material. The invention also relates to methods for making such aromatic polyester polyols and methods for using such aromatic polyester polyols to produce CASE materials. The invention further relates to cellular polyurethane and polyurethane/polyisocyanurate foams made using such aromatic polyester polyols. The polyester polyols of the present invention may be utilized with a wide variety of blowing agents, including water, hydrocarbon, chloroflurocarbon, and non-chlorofluorocarbon blowing agents.
The aromatic polyester polyols of the present invention can be readily blended with prior art polyols, if desired, and also with various additives conventionally used in the formulation of resin pre-polymer blends. The aromatic polyester polyols of the invention are prepared by an inter-esterification process that is simple, reliable, and well adapted for conventional chemical processing equipment.
In a first aspect, the invention provides low viscosity aromatic polyester polyols having an average functionality of about two. Thus, there is now provided an aromatic polyester polyol comprising the inter-esterification product of
(a) from about 20 to about 80 mole percent of at least one phthalic acid based material selected from the group consisting of phthalic anhydride, phthalic acid, isophthalic acid, terephthalic acid, methyl esters of phthalic, isophthalic, or terephthalic acid, dimethyl terephthalate, polyethylene terephthalate, trimellitic anhydride, pyromellitic dianhydride, maleic anhydride, or mixtures thereof;
b) from about 20 to about 80 mole percent of at least one low molecular weight aliphatic diol of the formula
HO—R
1
—OH
wherein R
1
is a divalent radical selected from the group consisting of
i) alkylene radicals each containing from 2 through 12 carbon atoms;
ii) radicals of the formula —[CH
2
—R
2
—CH
2
]— wherein R
2
is a radical selected from the group consisting of
iii) radicals of the formula
—[(R
3
O)
n
—R
3
]
wherein R
3
is an alkylene radical containing from 2-4 carbon atoms and n is an integer from 1 through 10;
or mixtures thereof;
c) from about 0.1 to about 20 mole percent of a higher functional polyol of the formula
HO—R
4
—OH
wherein R
4
is a divalent radical selected from the group consisting of
i) radicals of the formula —[CH
2
—R
5
—CH
2
]— wherein R
5
is a radical selected from the group consisting of
ii) radicals selected from the group consisting of glycerine, alkoxylated glycerine, sucrose, alkoxylated sucrose, methyl glucoside, alkoxylated methyl glucoside, glucose, alkoxylated glucose, fructose, alkoxylated frutose, sorbitol, alkoxylated sorbitol, lactose, and alkoxylated lactose;
or mixtures thereof; and
d) from about 0.1 to about 20 mole percent of at least one hydrophobic material characterized by
i) having an equivalent weight of about 130-1000;
ii) containing from about 8 to 60 carbon atoms; and
iii) containing at least one and not more than four radicals per molecule, which are selected from the group consisting of carboxyl, hydroxyl, and mixtures thereof.
The inter-esterification reaction may be performed with or without a suitable esterification catalyst. Typically, and preferably, the inter-esterification reaction is performed with a suitable esterification catalyst known to those of ordinary skill in the art. Although the above components may be combined in any order to produce the low viscosity aromatic polyester polyols of the invention, in a somewhat preferred embodiment, components (a), (b), and (c) initially are combined and the inter-esterification is allowed to proceed to substantial completion, forming an intermediate polyester polyol which is then inter-esterified with component (d) to form the low viscos
Acquah Samuel A.
McAndrews Held & Malloy Ltd.
Stepan Company
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