High performance ortho UPR

Details High performance ortho UPR High performance ortho UPR

2002-07-29

2004-02-24

Acquah, Samuel A. (Department: 1711)

Synthetic resins or natural rubbers -- part of the class 520 ser

Synthetic resins

Mixing of two or more solid polymers; mixing of solid...

C528S302000, C528S306000, C528S308000, C525S445000

Reexamination Certificate

active

06696521

ABSTRACT:

FIELD OF THE INVENTION
The invention relates to a high performance unsaturated polyester resin. In particular, the invention relates to the preparation of a high performance UPR from 2-methyl-1,3-propanediol.
BACKGROUND OF THE INVENTION
Unsaturated polyester resins (UPRs) are condensation polymers with a polyester backbone formed from a glycol and an unsaturated diacid. Commonly used unsaturated diacids are maleic acid, fumaric acid, and maleic anhydride. Even though fumaric acid offers many advantages in the production of UPRs, it is seldom used because it is usually expensive. Saturated diacids are often used with the unsaturated diacid to control the degree of unsaturation and to modify the physical properties of the UPR. There are two major types of UPRs: “ortho” and “iso.” Ortho UPR is made from phthalic anhydride and iso UPR from isophthalic acid. Ortho UPR costs less, but iso UPR performs better.
UPRs are crosslinked, through the unsaturation, with ethylenic monomers such as styrene. To cure well with styrene, the UPR needs a high degree of fumarate unsaturation (fumarate/maleate ratio greater than 90/10). Maleate-containing polyesters do not readily cure with styrene. However, most UPRs are commercially made from maleic anhydride. Thus, it is crucial to effectively isomerize maleate to fumarate during the condensation polymerization.
Many glycols are used for making UPRs. Examples are ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, and neopentyl glycol. The degree of isomerization of maleate to fumarate largely depends on the glycol used. In general, the use of a primary glycol leads to a low degree of isomerization, while the use of a secondary glycol leads to a high degree of isomerization. For instance, the esterification of maleic anhydride with neopentyl glycol, ethylene glycol, and propylene glycol gives fumarate/maleate ratios of 50/50, 75/25, and 93/7, respectively. See
Ind. Eng. Chem. Prod. Res. Dev
. 3(3), 218 (1964). Although propylene glycol gives a high fumarate content, it has lower reactivity toward condensation and the resultant UPR often has a dark color.
2-Methyl-1,3-propanediol (MPD) is a relatively new glycol sold by Lyondell Chemical Company as MPDiol™ glycol. It is a high boiling liquid, and it has two primary hydroxyl groups for rapid condensation. However, like other primary glycols, MPD disadvantageously gives UPRs with low fumarate/maleate ratios (from 60/40 to 70/30). Many efforts have been made to increase the fumarate content of UPRs made from MPD.
Co-pending Appl. Ser. No. 09/946,326 teaches a process for making unsaturated polyesters from MPD that have fumarate/maleate ratios greater than 85/15. However, the process requires the use of propylene glycol to boost the isomerization of maleate to fumarate in a late stage of the polymerization.
Co-pending Appl. Ser. No. 10/100,152 teaches a two-step process. In the first step, one equivalent of an aromatic diacid reacts with about two equivalents of MPD to produce an ester diol. In the second step, one equivalent of the ester diol reacts with from about 1.1 to about 1.9 equivalents of maleic anhydride to produce the polyester. This unsaturated polymer is then capped with suitable glycols or alcohols to produce low acid UPRs. The UPR has an increased fumarate/maleate ratio and improved performance. However, the process does not produce an ortho UPR that has the high performance of an iso UPR.
In sum, high-performance UPR is needed. Ideally, an ortho UPR would have the high performance of traditional iso UPR and could be made inexpensively.
SUMMARY OF THE INVENTION
The invention is a high performance UPR (unsaturated polyester resin). The UPR comprises recurring units of phthalic anhydride, 2-methyl-1,3-propanediol, and maleic anhydride. It has a fumarate/maleate ratio 85/15 or greater. It has a bi- or multi-modal molecular weight distribution. By “bi- or multi-modal,” we mean that the UPR shows at least two peaks in a GPC (gel permeation chromatography) spectrum. A high molecular weight portion of the UPR has a peak molecular weight (Mp) 50,000 or greater. The UPR has a weight average molecular weight 10,000 or greater. Surprisingly, an ortho UPR of the invention performs as well as or better than traditional iso UPR.
The invention includes a process for making a UPR. The process comprises two steps. First, a mixture comprising phthalic anhydride (PA), 2-methyl-1,3-propanediol (MPD), and maleic anhydride (MA) is polymerized by condensation. The mixture has a (PA+MA)/MPD molar ratio greater than 1. Second, more MPD is added to the resin of step 1. The total moles of MPD added in steps 1 and 2 is greater than the combined moles of PA and MA added in step 1. The polymerization continues to form a UPR having a bi- or multi-modal molecular weight distribution.
DETAILED DESCRIPTION OF THE INVENTION
The invention is a UPR (unsaturated polyester resin). The UPR comprises recurring units of phthalic anhydride, 2-methyl-1,3-propanediol, and maleic anhydride.
Optionally, the UPR of the invention comprises other recurring units. It may comprise recurring units of other glycols. Suitable glycols include ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, 1,2-butanediol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2-dimethyl-1,3-propanediol, cyclohexane-1,4-dimethanol, and neopentyl glycol, the like, and mixtures thereof. Using other glycols can lower the cost or modify the properties of the UPR. For instance, ethylene glycol is relatively inexpensive. Using diethylene glycol can improve the flexibility of the UPR.
The UPR may comprise recurring units of alcohols. Suitable alcohols include C
3
to C
10
alcohols. Alcohols are used to control molecular weight or modify the properties of the UPR. Sterically bulky alcohols, such as 2-ethylhexan-1-ol, 2-methylhexan-2-ol, 3-methylpentan-3-ol, 2-methylpentan-2-ol, 3-methyl-2-butanol, 2-methylbutan-2-ol, and 3-methyl-2-butanol, are preferred. Suitable alcohols can also be ethylenically or acetylenically unsaturated, for example, 2-methyl-3-buten-2-ol and 3-methyl-1-penten-3-ol. Alcohols are preferably used in an amount less than 10% of the glycol(s).
The UPR may comprise recurring units of other acid derivatives. Suitable acid derivatives include C
3
to C
10
aliphatic, C
3
to C
10
cyclic, and C
8
to C
20
aromatic di- or multifunctional acids. Examples of suitable acids include succinic, oxalic, malonic, glutaric, adipic, pimelic, suberic, azelaic, and sebacic acids, cyclohexanedicarboxylic acid, isophthalic acid, terephthalic acid, and the like.
The recurring units of unsaturated (fumaric and maleic) acids are preferably greater than 35% of the total acids. More preferably, the recurring units of unsaturated acids are greater than 45% of the total acids. Most preferably, the recurring units of the unsaturated acids are greater than 50% of the total acids.
The UPR of the invention has a fumarate/maleate ratio at least 85/15. Preferably, the fumarate/maleate ratio is at least 90/10. More preferably, the fumarate/maleate ratio is at least 95/5. The higher the fumarate/maleate ratio, the more reactive the UPR. Conventional UPR made from 2-methyl-1,3-propanediol has low fumarate content and thus low performance. See Comparative Example 2.
The UPR has a bi- or multi-modal molecular weight distribution. A high molecular weight portion of the distribution has a peak molecular weight (Mp) 50,000 or greater. Preferably, the Mp is 75,000 or greater. More preferably, the Mp is 100,000 or greater. Preferably, the high molecular weight portion is from 2% to about 50% by weight of the total resin composition. More preferably, the high molecular weight portion is from 5% to about 25% of the total resin composition.
The UPR has a weight average molecular weight (Mw) 10,000 or greater. Preferably, Mw is 20,000 or greater. More preferably, Mw is 30,000 or greater. Most preferably, Mw is 35,000 or greater. The Mw of the UPR is significantly greater than the conventional UPR. Usually, a conventional UPR has Mw less tha

Affiliated with

Also associated with

Rating

High performance ortho UPR does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with High performance ortho UPR, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and High performance ortho UPR will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-3317463