**6. Process parameters**

Now it is useful to observe Table 5. In this table are resumed the conditions of the different processes used for recovering BPA from waste PC by using alcoholysis or hydrolysis.


Table 5. Comparison among obtained results in recovering BPA from PC by alcoholysis or hydrolysis (n.a. = not available, BPA yield=kg BPa/kgPC).

The hydrolysis or methanolysis process can be performed at a temperature level that avoid pyrolysis. It can be observed that, with exception of the paper of Hu et al., 1998, were toluene is used, all the activation energies are very close. This means that the elementary processes and the reaction mechanisms are extremely similar. Most probably they are dominated by mass diffusion limitation. The BPA yield indicate that about complete decomposition of the polymer occurs with water.

Essentially in order to make some observations regarding a possible process that adopts the hydrolysis method, it can be observed that it has to comprise the following aspects: the chopping of the solid materials and the particles dispersion into water; the compression of the suspension till the proper pressure (e.g. 4-8 MPa); the heating of the mixture till the maximum temperature (280-290°C), possibly by superheated pressure steam; the cooling of the reacted mixture by flashing after the convenient reaction time (recovering the steam), till a relatively low pressure (0.5 MPa) allowing the recovery of the molten monomer for the decantation of the suspended inert solid particles; the clean liquid monomer (at 140-160°C) is separated from the remaining small amount of the practically immiscible water and then sent to subsequent conventional purification steps.

Some processes have been already patented by important societies. A list is following: General Electric (Fox D.W. & Peters E.N., 1989; Shaffer S.J., 1994; Caruso A.J. & Lee J.L., 1996; Eijsbouts P. et al., 1997), Bayer AG (Buysch H.J. & Schoen N., 1993; Buysch H.J. et al., 1994; Buysch H.J., 1995), Teijin Chemicals LTD (Kiyoshije K. & Matsumoto K., 1994; Suzuki M. & Matsumoto K., 1995; Suzuki M., 1995, Ogasawara K. & Matsuura T., 2004, Takemoto H., 2005), Mitsubishi Heavy Ind. LTD (Hishihara N. et al., 1999; Hishihara et al., 2001), Victor Company of Japan (Takahashi T. et al., 2001; Tsujita K. et al., 2001a; Tsujita K. et al., 2001b; Tsujita K. et al., 2001c; Tsujita K. et al., 2001d; Kawai N., 2002; Tsujita K. & Kawai N., 2004; Tsujita K. & Kawai N., 2005), Kansai Res. Inst. (Kawashima F. et al., 2003).

#### **7. Conclusions**

128 Material Recycling – Trends and Perspectives

Now it is useful to observe Table 5. In this table are resumed the conditions of the different

Piñero et al., 2005 CH3OH/NaOH 80-90% 70-180 2-25 45-130 87.58 Hu et al., 1998 CH3OH/C7H8 7-96% 40-60 0.1 15-330 107.5 Dongpil et al., 2009 CH3OH 90-96% 160-220 n.a. 40-180 79.5 Jie et al., 2006 C2H5OH 20-90% 240-290 n.a. 10-60 97.2 Chen et al., 2004 CH3OH 20-90% 230-265 7.8-10 10-30 75.72 Bozzano et al., 2010 H2O 80-90% 240-290 4-8 20-240 84

Table 5. Comparison among obtained results in recovering BPA from PC by alcoholysis or

The hydrolysis or methanolysis process can be performed at a temperature level that avoid pyrolysis. It can be observed that, with exception of the paper of Hu et al., 1998, were toluene is used, all the activation energies are very close. This means that the elementary processes and the reaction mechanisms are extremely similar. Most probably they are dominated by mass diffusion limitation. The BPA yield indicate that about complete

Essentially in order to make some observations regarding a possible process that adopts the hydrolysis method, it can be observed that it has to comprise the following aspects: the chopping of the solid materials and the particles dispersion into water; the compression of the suspension till the proper pressure (e.g. 4-8 MPa); the heating of the mixture till the maximum temperature (280-290°C), possibly by superheated pressure steam; the cooling of the reacted mixture by flashing after the convenient reaction time (recovering the steam), till a relatively low pressure (0.5 MPa) allowing the recovery of the molten monomer for the decantation of the suspended inert solid particles; the clean liquid monomer (at 140-160°C) is separated from the remaining small amount of the practically immiscible water and then

Some processes have been already patented by important societies. A list is following: General Electric (Fox D.W. & Peters E.N., 1989; Shaffer S.J., 1994; Caruso A.J. & Lee J.L., 1996; Eijsbouts P. et al., 1997), Bayer AG (Buysch H.J. & Schoen N., 1993; Buysch H.J. et al., 1994; Buysch H.J., 1995), Teijin Chemicals LTD (Kiyoshije K. & Matsumoto K., 1994; Suzuki M. & Matsumoto K., 1995; Suzuki M., 1995, Ogasawara K. & Matsuura T., 2004, Takemoto H., 2005), Mitsubishi Heavy Ind. LTD (Hishihara N. et al., 1999; Hishihara et al., 2001), Victor Company of Japan (Takahashi T. et al., 2001; Tsujita K. et al., 2001a; Tsujita K. et al., 2001b; Tsujita K. et al., 2001c; Tsujita K. et al., 2001d; Kawai N., 2002; Tsujita K. & Kawai N.,

2004; Tsujita K. & Kawai N., 2005), Kansai Res. Inst. (Kawashima F. et al., 2003).

yield T [°C] <sup>P</sup>

[MPa]

Time [min] Activation Energy [kJ/mol]

processes used for recovering BPA from waste PC by using alcoholysis or hydrolysis.

**6. Process parameters** 

Authors Reactant BPA

hydrolysis (n.a. = not available, BPA yield=kg BPa/kgPC).

decomposition of the polymer occurs with water.

sent to subsequent conventional purification steps.

In this chapter the experimental results of the hydrolysis of poly(bisphenol A carbonate) with water have been presented together with a description of existing methods for recycling PC. Both pure PC and CDs waste have been treated. The adopted temperature levels are subcritical and pressures inside the reactor allow to hydrolyze with liquid water. The tests have shown the feasibility of the process that in these conditions is mainly based on real molecular concerted path reactions. Secondary reactions, requiring a radical path and leading to parasitic byproducts, are characterized by quite higher apparent activation energy and require higher temperature levels than those here adopted. For this reason in the presented process they are negligible.

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**5** 

**PVB Sheet Recycling and Degradation** 

Michael Tupý1, Dagmar Měřínská1,2 and Věra Kašpárková2,3

*<sup>2</sup>Centre of Polymer Systems, University Institute, Tomas Bata University in Zlin, Zlin, <sup>3</sup>Department of Fat, Surfactant and Cosmetics Technology, Faculty of Technology,* 

Increasing growth of raw material prices, environmental aspects and still growing landfill fees bring about the increasing interest encountered with the plastics waste recycling. Globally, the problem has been solved for the common plastics such as polyolefins, poly(ethylene terephtalate) and poly(styrene). Though extensively used for the glass lamination, poly(vinyl butyral) (PVB) does not belong to this group. It is generally known

The PVB polymer is mostly used in the form of plasticized PVB sheet for preparation of laminated safety glass (LSG). At present time, Solutia, DuPont, Seki sui and Kuraray are worldwide PVB manufacturers. The PVB is the material which can stick together float glasses with holding excellent optical and mechanical properties of the glass laminate (Ivanov, 2006; v. Elasticity, mechanical strength, toughness, high light transmission and the adhesion to glass are the most significant PVB properties (Tupý, Měřínská, et al, 2010). Toughness of PVB sheet is based on high molecular weight of PVB chain. Certainly, the PVB has to be plasticized for achieving high material elasticity (Iwasaki, et al, 2006; Keller, Mortelmans, 1999; Svoboda, Balazs., et al, 1988). Admittedly, the plasticizer must not reduce light transmittance through the sheet, PVB adhesion to glass, generate haze and yellowness, and migrate out of the polymer matrix (Wade, D'Errico, et al, 2004). In addition, plasticizer must have perfect

that during the glass lamination process, large volume of PVB trim is formed.

compatibility with the polymer and low evaporability during processing conditions.

Worldwide, 65% of all PVB sheets are used in automotive applications (Dhaliwal, Hay, 2002). According to data from (OCIA, 2007), the worldwide car's production is estimated around 60 millions cars per a year. Assuming that one windshield contains approx. 1 kg of PVB sheet, total amount gives between 60-70 million kg of PVB sheets per year. In addition, by-products from PVB sheets manufacturing (5%) and trimmings (< 10%) from windshield production must be added (Goroghovski, Escapante-Garcia, et al, 2005). It represents total amount of 80 million kg of automotive PVB sheet waste annually. Total worldwide amount of produced PVB sheets for automotive and architectural industry is estimated around 120

**2. Sources for recycling of PVB sheet** 

million kg per year.

**1. Introduction** 

*<sup>1</sup>Department of Polymer Engineering, Faculty of Technology,* 

*Tomas Bata University in Zlin, Zlin,*

*Tomas Bata University in Zlin, Zlin,* 

*Czech Republic*

